fix: reuse open app-deploy grants

[JuaniRios]

Motivation

• The revoke path added in fix: revoke superseded active deploy grants #8 fails because the app releaser does not have the revoke permission.
• We need the current liquidity config rollout. We will fix the Privileged Access Manager permissions separately.

Solution

• Reuse any active or pending app-deploy grant without comparing its justification.
• Remove the grant replacement and revoke path.
• Cover both ACTIVE and APPROVAL_AWAITED grant reuse in the workflow tests.
• A release can temporarily use a grant approved for a different earlier release while that grant remains open.

Checks

By submitting this for review, I'm confirming I've done the following:

• added comprehensive test coverage for any changes in logic
• made this PR as small as possible
• linked any relevant issues or PRs
• included screenshots (not applicable)

[JuaniRios]

• fix: reuse open app-deploy grants #9 👈 (View in Graphite)
• main

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