fix(rust: builder): add lifetime bounds to finish methods

[dallasmarlow]

This change addresses a reported issue where a FlatBufferBuilder could be finished with a WIPOffset created by a different builder.

Calling builder1.finish(offset_from_builder2) would compile but result in a runtime panic or data corruption, as the offset is meaningless in builder1's buffer.

The fix enforces the builder's lifetime ('fbb) on the generic type T of the WIPOffset in all finish methods (finish, finish_minimal, finish_size_prefixed, and finish_with_opts).

https://github.com/google/flatbuffers/issues/8698

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[jtdavis777]

this seems good to me (as a rust n00b) -- is there a way we can write a regression test against this as part of this PR?