Shrink request to throw IllegalArgumentException when index not write blocked

[monusingh-1]

Description

This change changes the Exception thrown when shrink operation is performed on an index which does not have write block from IllegalStateException(5xx) to IllegalArgumentException(4xx)

Related Issues

Resolves #[19026]

Testing

curl -X POST "localhost:9200/test-01/_shrink/test-shrink-01" -H 'Content-Type: application/json' -d'              15:57:01
{
  "settings": {
    "index.number_of_shards": 1,
    "index.number_of_replicas": 0
  }
}'

Before

{"error":{"root_cause":[{"type":"illegal_state_exception","reason":"index test-01 must block write operations to resize index. use "index.blocks.write=true""}],"type":"illegal_state_exception","reason":"index test-01 must block write operations to resize index. use "index.blocks.write=true""},"status":500}

After

{"error":{"root_cause":[{"type":"illegal_argument_exception","reason":"index test-01 must block write operations to resize index. use "index.blocks.write=true""}],"type":"illegal_argument_exception","reason":"index test-01 must block write operations to resize index. use "index.blocks.write=true""},"status":400}%

Check List

• Functionality includes testing.
• 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 2df8790: 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?