fix: Add declare explicitly for operator overload error

[yabinma]

For fixing overload error in gcc 13.2 on Ubuntu 24.04

Error log,

/opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/common/StreamIdentifier.h:40:16: error: ‘virtual bool facebook::velox::dwio::common::StreamIdentifier::operator==(const facebook::velox::dwio::common::StreamIdentifier&) const’ was hidden [-Werror=overloaded-virtual=]
   40 |   virtual bool operator==(const StreamIdentifier& other) const {
      |                ^~~~~~~~
In file included from /opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/dwrf/common/ByteRLE.h:27,
                 from /opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/dwrf/reader/ColumnReader.h:24,
                 from /opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/dwrf/reader/SelectiveDwrfReader.h:20,
                 from /opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/dwrf/reader/DwrfReader.h:23,
                 from /opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/orc/reader/OrcReader.h:20,
                 from /opt/gitspace/incubator-gluten/cpp/velox/compute/VeloxBackend.cc:47:
/opt/gitspace/incubator-gluten/dev/../ep/build-velox/build/velox_ep/velox/dwio/dwrf/common/Common.h:196:8: note:   by ‘bool facebook::velox::dwrf::DwrfStreamIdentifier::operator==(const facebook::velox::dwrf::DwrfStreamIdentifier&) const’
  196 |   bool operator==(const DwrfStreamIdentifier& other) const {
      |        ^~~~~~~~

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