fix: support int64 indices for embedding

[fs-eire]

Description

Allow embedding conversion to accept TensorRT int32 and int64 indices.

There used to be a restriction that TensorRT v8.x only works with int32 indices for embedding op, but since TensorRT v9, int64 is supported. We no longer need to reject int64 indices now.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
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