feat: [Spanner] add a last field in the PartialResultSet (#8112)

* feat: add a last field in the PartialResultSet
docs: A comment for field `rows` in message `.google.spanner.v1.ResultSet` is changed
docs: A comment for field `stats` in message `.google.spanner.v1.ResultSet` is changed
docs: A comment for field `precommit_token` in message `.google.spanner.v1.ResultSet` is changed
docs: A comment for field `values` in message `.google.spanner.v1.PartialResultSet` is changed
docs: A comment for field `chunked_value` in message `.google.spanner.v1.PartialResultSet` is changed
docs: A comment for field `stats` in message `.google.spanner.v1.PartialResultSet` is changed
docs: A comment for field `precommit_token` in message `.google.spanner.v1.PartialResultSet` is changed
docs: A comment for message `ResultSetMetadata` is changed
docs: A comment for field `row_type` in message `.google.spanner.v1.ResultSetMetadata` is changed
docs: A comment for message `ResultSetStats` is changed
docs: A comment for field `query_plan` in message `.google.spanner.v1.ResultSetStats` is changed
docs: A comment for field `row_count_lower_bound` in message `.google.spanner.v1.ResultSetStats` is changed

PiperOrigin-RevId: 730849734

Source-Link: googleapis/googleapis@fe0fa26

Source-Link: googleapis/googleapis-gen@16051b5
Copy-Tag: eyJwIjoiU3Bhbm5lci8uT3dsQm90LnlhbWwiLCJoIjoiMTYwNTFiNTkxN2I3NWY2MDNjY2I1ZjQ3N2UyYTQ2NDdiYTExZmE4MiJ9

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Spanner/tests/Unit/V1/Client/SpannerClientTest.php

@@ -661,21 +661,27 @@ public function executeStreamingSqlTest()
         // Mock response
         $chunkedValue = true;
         $resumeToken2 = '90';
+        $last = true;
         $expectedResponse = new PartialResultSet();
         $expectedResponse->setChunkedValue($chunkedValue);
         $expectedResponse->setResumeToken($resumeToken2);
+        $expectedResponse->setLast($last);
         $transport->addResponse($expectedResponse);
         $chunkedValue2 = false;
         $resumeToken3 = '91';
+        $last2 = false;
         $expectedResponse2 = new PartialResultSet();
         $expectedResponse2->setChunkedValue($chunkedValue2);
         $expectedResponse2->setResumeToken($resumeToken3);
+        $expectedResponse2->setLast($last2);
         $transport->addResponse($expectedResponse2);
         $chunkedValue3 = true;
         $resumeToken4 = '92';
+        $last3 = true;
         $expectedResponse3 = new PartialResultSet();
         $expectedResponse3->setChunkedValue($chunkedValue3);
         $expectedResponse3->setResumeToken($resumeToken4);
+        $expectedResponse3->setLast($last3);
         $transport->addResponse($expectedResponse3);
         // Mock request
         $formattedSession = $gapicClient->sessionName('[PROJECT]', '[INSTANCE]', '[DATABASE]', '[SESSION]');
@@ -1182,21 +1188,27 @@ public function streamingReadTest()
         // Mock response
         $chunkedValue = true;
         $resumeToken2 = '90';
+        $last = true;
         $expectedResponse = new PartialResultSet();
         $expectedResponse->setChunkedValue($chunkedValue);
         $expectedResponse->setResumeToken($resumeToken2);
+        $expectedResponse->setLast($last);
         $transport->addResponse($expectedResponse);
         $chunkedValue2 = false;
         $resumeToken3 = '91';
+        $last2 = false;
         $expectedResponse2 = new PartialResultSet();
         $expectedResponse2->setChunkedValue($chunkedValue2);
         $expectedResponse2->setResumeToken($resumeToken3);
+        $expectedResponse2->setLast($last2);
         $transport->addResponse($expectedResponse2);
         $chunkedValue3 = true;
         $resumeToken4 = '92';
+        $last3 = true;
         $expectedResponse3 = new PartialResultSet();
         $expectedResponse3->setChunkedValue($chunkedValue3);
         $expectedResponse3->setResumeToken($resumeToken4);
+        $expectedResponse3->setLast($last3);
         $transport->addResponse($expectedResponse3);
         // Mock request
         $formattedSession = $gapicClient->sessionName('[PROJECT]', '[INSTANCE]', '[DATABASE]', '[SESSION]');