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
try {
                
                final Set<Index> indicesToOpen = Sets.newLinkedHashSetWithExpectedSize(taskContexts.size());
                for (final var taskContext : taskContexts) {
                    Collections.addAll(indicesToOpen, taskContext.getTask().request.indices());
                }
                Index[] indices = indicesToOpen.toArray(Index.EMPTY_ARRAY);
                
                state = openIndices(indices, state);
                
                state = allocationService.reroute(state, "indices opened");
                for (final var taskContext : taskContexts) {
                    final var task = taskContext.getTask();
                    taskContext.success(task);
                }
            } catch (Exception e) {
                for (final var taskContext : taskContexts) {
                    taskContext.onFailure(e);
                }
            }
            return state;
        }
        private ClusterState openIndices(final Index[] indices, final ClusterState currentState) {
            final List<IndexMetadata> indicesToOpen = new ArrayList<>(indices.length);
            for (Index index : indices) {
                final IndexMetadata indexMetadata = currentState.metadata().getIndexSafe(index);
                if (indexMetadata.getState() != IndexMetadata.State.OPEN) {
                    indicesToOpen.add(indexMetadata);
                } else if (currentState.blocks().hasIndexBlockWithId(index.getName(), INDEX_CLOSED_BLOCK_ID)) {
                    indicesToOpen.add(indexMetadata);