[CELEBORN-1318][FOLLOWUP] Authenticate bearer token directly

[turboFei]

What changes were proposed in this pull request?

I am working on the bearer token authentication integration, and meet the token base64 decode issue.

And found that, for bear token, we shall authenticate it directly.

Why are the changes needed?

For bearer authentication issue.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Integration testing.

[turboFei]

cc @pan3793

[pan3793]

merged to main