What this PR does / why we need it

Closes #6163

Feature view versioning was introduced in #6101, but version-qualified feature references (e.g.
driver_stats@v2:trips_today) only worked with the SQLite online store. All other online stores raised
VersionedOnlineReadNotSupported when a versioned ref was used.

This PR adds versioned read/write support to the DynamoDB online store, following the same pattern as the
SQLite reference implementation:

• Write path: when enable_online_feature_view_versioning is enabled, _get_table_name appends a _v{N} suffix
  to the DynamoDB table name (e.g. project.driver_stats_v2), routing materialization to the correct versioned
  table
• Read path: version-qualified lookups (@v2) set projection.version_tag on the feature view before
  online_read is called; _get_table_name picks this up and routes to the correct table. projection.version_tag
  takes priority over current_version_number so explicit version requests are always honoured
• Gate: _check_versioned_read_support in online_store.py now allows DynamoDBOnlineStore through, covering
  both sync and async read paths

All existing read/write/update/teardown methods are covered by the single change to _get_table_name since
every method routes through it.

Which issue(s) this PR fixes

Part of #2728

Checks

• I've made sure the tests are passing.
• My commits are signed off (git commit -s)
• My PR title follows conventional commits format

Testing Strategy

• Unit tests — 6 new unit tests for _get_table_name covering: versioning disabled, projection.version_tag
  priority, current_version_number fallback, version 0 edge case, no version info, custom template
• Manual tests — end-to-end smoke test using moto (mocked DynamoDB) exercising write → read round trips
  across v1/v2 isolation, fallback behaviour, and missing entity handling

Misc

The version suffix is composed before the table_name_template is applied, so custom table_name_template
values (e.g. "{project}__{table_name}") continue to work correctly with versioning enabled.