[flink] Support ALTER MATERIALIZED TABLE ... AS <query> in FlinkCatalog

[xuyangzhong]

Purpose

Linked issue: close #3595

FlinkCatalog#alterTable cannot alter a materialized table's definition query.
Running ALTER MATERIALIZED TABLE <tbl> AS <new_query> makes Flink emit a
TableChange.ModifyDefinitionQuery, which FlinkConversions does not recognize
and rejects with UnsupportedOperationException: Unsupported flink table change.

ModifyDefinitionQuery was introduced in Flink 2.0, so it cannot be referenced
directly from fluss-flink-common (compiled against an older Flink baseline).
This PR adds support in a way that keeps the shared module compilable while
letting version-specific modules convert newer table changes.

Brief change log

• Add a version-agnostic TableChangeAdapter in fluss-flink-common whose
  default convert(...) returns Optional.empty() (nothing version-specific to
  convert for the compile baseline).
• Override TableChangeAdapter in fluss-flink-2.2 to convert
  TableChange.ModifyDefinitionQuery into a Fluss SetOption on
  materialized-table.definition-query. New version-specific changes only need a
  new branch here in the future.
• Route any unrecognized TableChange in FlinkConversions#toFlussTableChanges
  through TableChangeAdapter.convert(...) before throwing
  UnsupportedOperationException, so no call-site changes are needed later.

Tests

• Flink22TableChangeAdapterTest: ModifyDefinitionQuery is converted to the
  expected SetOption; an unhandled change (ModifyRefreshStatus) returns
  Optional.empty().
• Flink22FlinkConversionsTest: FlinkConversions.toFlussTableChanges maps
  ModifyDefinitionQuery to a SetOption on materialized-table.definition-query.
• Flink22MaterializedTableITCase:
  • testAlterMaterializedTableAsQueryInContinuousMode: alter the definition
    query (same output schema) and verify the query/refresh job are updated.
  • testAlterMaterializedTableAsQueryWithAppendColumn: append a nullable column
    at the end (the only schema evolution Flink allows for materialized tables).
  • testAlterMaterializedTableAsQueryWithUnsupportedSchemaChange: dropping and
    reordering columns are rejected by the Flink planner.

API and Format

No. No public API or storage format changes; only the existing
materialized-table.definition-query option is written on alter.

Documentation

Later.