[Remote Store] Using RemoteDirectory#delete to clear all segments during migration

[gbbafna]

Description

getRemoteDirectory().deleteStaleSegments will not delete last metadata when pinned timestamps are enabled . Hence we need to use getRemoteDirectory().delete(); which does the clean up comprehensively .

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

• Functionality includes testing. Existing integ tests cover this.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

❌ Gradle check result for 86c6e1c: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?