CCR needs to revisit index settings when resuming following

[jasontedor]

Today this is possible, and CCR will fail:

• close the leader index
• add a new analyzer to the index settings
• update the mapping adding a field referencing the new analyzer
• open the leader index
• resume the follower
• 💥

The follower will fail when updating the mapping since it references an analyzer that the follower does not know about. At this point, manual intervention is required on the follower to address.

Instead, we need to revisit the index settings on the leader when resuming following.

[elasticmachine]

Pinging @elastic/es-distributed

[jasontedor]

Closed by #35089