fix: Ignore AWSAccessKeyId check for SignV2 policy condition

[jiuker]

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Description

fix: Ignore AWSAccessKeyId check for SignV2 policy condition

Motivation and Context

How to test this PR?

UT should cover this.

Types of changes

• Bug fix Bug in postpolicyform.go signed uploads with POST request always fail with 403 error : must appear in the list of conditions.  #19652
• New feature (non-breaking change which adds functionality)
• Optimization (provides speedup with no functional changes)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression (If yes, please add commit-id or PR # here)
• Unit tests added/updated
• Internal documentation updated
• Create a documentation update request here

[harshavardhana]

Please add a test case that covers these usecases..

[shtripat]

lgtm