Tiny supportability nit: today we emit these log messages when adding a write block to an index:

```
[2022-03-22T19:43:26,897][INFO ][o.e.c.m.MetadataIndexStateService] [node_t1] adding block write to indices [[test-blocks/eLkrYpm_S3WNemfWpXrhPA]]
[2022-03-22T19:43:26,933][INFO ][o.e.c.m.MetadataIndexStateService] [node_t1] completed adding block write to indices [test-blocks]
```

This is kind of confusing, a `block write` sounds like we're writing a block of data. It's not clear that `write` is variable (we also say `block read`) or the name of a block setting. I think we should word this as `adding [index.blocks.write] block to indices` instead.
server/src/main/java/org/elasticsearch/cluster/metadata/MetadataIndexStateService.java
INDEX_CLOSED_BLOCK_ID,
            UUIDs.randomBase64UUID(),
            "index preparing to close. Reopen the index to allow writes again or retry closing the index to fully close the index.",
            false,
            false,
            false,
            RestStatus.FORBIDDEN,
            EnumSet.of(ClusterBlockLevel.WRITE)
        );
    }
    public static boolean isIndexVerifiedBeforeClosed(final IndexMetadata indexMetadata) {
        return indexMetadata.getState() == IndexMetadata.State.CLOSE
            && VERIFIED_BEFORE_CLOSE_SETTING.exists(indexMetadata.getSettings())
            && VERIFIED_BEFORE_CLOSE_SETTING.get(indexMetadata.getSettings());
    }
    
    public static ClusterBlock createUUIDBasedBlock(ClusterBlock clusterBlock) {
        assert clusterBlock.uuid() == null : "no UUID expected on source block";
        return new ClusterBlock(
            clusterBlock.id(),
            UUIDs.randomBase64UUID(),
            "moving to block " + clusterBlock.description(),
            clusterBlock.retryable(),
            clusterBlock.disableStatePersistence(),
            clusterBlock.isAllowReleaseResources(),
            clusterBlock.status(),
            clusterBlock.levels()
        );
    }
    private class OpenIndicesExecutor implements ClusterStateTaskExecutor<OpenIndicesTask> {