Disable flake selenium tests (backport #15032)

[mergify]

Disable two selenium flake tests due to race condition. It is necessary to modify the
implementation to avoid race-condition.

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes issue #NNNN)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI
  .

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This is an automatic backport of pull request #15032 done by [Mergify](https://mergify.com).