bigtable: Allow microseconds for TimestampRangeFilter in emulator

[mathanv91]

Is your feature request related to a problem? Please describe.

There was this issue that was raised in 2022~ regarding allowing microseconds precision for TimestampRangeFilter. It looks like this issue is relevant now since the Bigtable service is accepting these but not the Bigtable emulator.

When running this mutation which contains a TimestampRangeFilter against the Bigtable emulator for this conditional row mutation:

ConditionalRowMutation conditionalRowMutation =
              ConditionalRowMutation.create(
                      <tableName>, <key>)
                  .condition(
                      FILTERS
                          .chain()
                          .filter(
                              FILTERS.timestamp().exact(<timestamp>)))
                  .then(rowMutation);

I get the following error that I don't get when running against a Bigtable instance.

Caused by: com.google.api.gax.rpc.InvalidArgumentException: io.grpc.StatusRuntimeException: INVALID_ARGUMENT: Error in field 'timestamp_range_filter'. Maximum precision allowed in filter is millisecond.
Got:
Start: 1702478558245000
End: 1702478558245001

Describe the solution you'd like

Allowing microseconds precision for TimestampRangeFilter as suggested from the original issue if this is allowed now.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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