[BUG] Shard fails on flush due to exception during prepareAndUpload in RemoteFsTranslog for remote indexes

[ashking94]

Describe the bug
While running stress testing on a remote enabled cluster, observed the behaviour where if the upload to remote store throws an exception, the shard will fail and the indexes become red with underlying shard becoming unassigned on account of flush being triggered internally or externally.

To Reproduce
Throw exception from prepareAndUpload while doing flush.

Expected behavior
Shard should not fail

Plugins
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Host/Environment (please complete the following information):

• OS: [e.g. iOS]
• Version [e.g. 22]

Additional context
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