Fix clippy::unnecessary_map_or warning

```
error: this `map_or` is redundant
   --> tf_rosrust/src/tf_buffer.rs:95:24
    |
95  |                       if self
    |  ________________________^
96  | |                         .transform_data
97  | |                         .get(&TfGraphNode {
98  | |                             child: v.clone(),
99  | |                             parent: current_node.clone(),
100 | |                         })
101 | |                         .map_or(false, |chain| chain.has_valid_transform(time))
    | |_______________________________________________________________________________^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_map_or
    = note: `-D clippy::unnecessary-map-or` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::unnecessary_map_or)]`
help: use is_some_and instead
    |
95  ~                     if self
96  +                         .transform_data
97  +                         .get(&TfGraphNode {
98  +                             child: v.clone(),
99  +                             parent: current_node.clone(),
100 +                         }).is_some_and(|chain| chain.has_valid_transform(time))
    |
```

tf_r2r/src/tf_buffer.rs

@@ -99,7 +99,7 @@ impl TfBuffer {
                             child: v.clone(),
                             parent: current_node.clone(),
                         })
-                        .map_or(false, |chain| chain.has_valid_transform(time))
+                        .is_some_and(|chain| chain.has_valid_transform(time))
                     {
                         parents.insert(v.to_string(), current_node.clone());
                         frontier.push_front(v.to_string());

tf_rosrust/src/tf_buffer.rs

@@ -98,7 +98,7 @@ impl TfBuffer {
                             child: v.clone(),
                             parent: current_node.clone(),
                         })
-                        .map_or(false, |chain| chain.has_valid_transform(time))
+                        .is_some_and(|chain| chain.has_valid_transform(time))
                     {
                         parents.insert(v.to_string(), current_node.clone());
                         frontier.push_front(v.to_string());