[Segment Replication] Write a test for mixed cluster segrep enabled POC

[Poojita-Raj]

This is the first step as part of the POC in issue #6211 :

Create a test that fails when mixed clusters with segment replication enabled does not work as expected.

Starting with the test we can work backwards to create a poc. Once this test passes with the poc, we can then revisit all the components to ensure a strong testing framework by adding more unit and integration tests.

Test specifications:

• Create a segment replication enabled cluster with 1 cluster manager and 2 data nodes all on the same OS version.
• Set up 1 replica for this cluster.
• Check that the indexing, deleting and updating operations take place as expected.
• Change version of replica nodes to a higher version and again check that indexing, deleting and updating operations take place as expected.
• Update primary nodes version to the same as the replica. Again check that indexing, deleting and updating operations take place as expected.
• Now update the primary yet again. This time if mixed cluster POC is not correctly implemented, it will not be able to perform the indexing, deleting and updating operations without error.

[Poojita-Raj]

Closed this out as this solution was discarded in favor of the shard_movement_strategy setting as mentioned in #3881