UtcOffset should reject when the offset is subminute precision.

[nekevss]

The line this most likely should be applied is here. Although we should double check it isn't meant to be applied elsewhere.

For reference to the specification step, see ParseTimeZoneIdentifier step 4.b.

[nekevss]

To continue on the above introduction, this will require changes upstream to ixdtf.

Currently, ixdtf only has one UtfOffsetRecord, and this will probably need to be updated to an enum with a MinutePrecisionOffset and FullPrecisionOffset.

The reason being is that a string like 2025-03-02T08:58:00-06:00:00 with sub minute precision cannot be reliably differentiated from 2025-03-02T08:58:00-06:00.