Remove empty alias from StorageType

[Anaethelion]

This remove what seems to be a leftover alias on the StorageType enum.

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
indices.add_block	🔴	1/2	1/2
indices.analyze	🔴	19/20	19/20
indices.clear_cache	🔴	3/4	3/4
indices.clone	🔴	4/5	4/5
indices.close	🔴	48/49	48/49
indices.create_data_stream	🔴	27/28	27/28
indices.create	🔴	871/891	890/891
indices.data_streams_stats	🔴	3/4	3/4
indices.delete_alias	🔴	14/15	4/15
indices.delete_data_lifecycle	⚪	Missing test	Missing test
indices.delete_data_stream	🔴	27/28	27/28
indices.delete_index_template	🔴	0/1	0/1
indices.delete_template	🔴	8/9	8/9
indices.delete	🔴	104/105	104/105
indices.disk_usage	🔴	4/5	4/5
indices.downsample	🔴	0/1	0/1
indices.exists_alias	🔴	35/36	35/36
indices.exists_index_template	⚪	Missing test	Missing test
indices.exists_template	🔴	14/15	14/15
indices.exists	🔴	38/39	38/39
indices.explain_data_lifecycle	⚪	Missing test	Missing test
indices.field_usage_stats	🔴	4/5	4/5
indices.flush	🔴	15/16	15/16
indices.forcemerge	🔴	6/7	5/7
indices.get_alias	🔴	82/83	70/83
indices.get_data_lifecycle	⚪	Missing test	Missing test
indices.get_data_stream	🔴	11/12	2/12
indices.get_field_mapping	🔴	14/15	13/15
indices.get_index_template	🔴	18/19	14/19
indices.get_mapping	🔴	92/93	88/93
indices.get_settings	🔴	55/56	53/56
indices.get_template	🔴	29/30	29/30
indices.get	🔴	52/53	52/53
indices.migrate_to_data_stream	⚪	Missing test	Missing test
indices.modify_data_stream	⚪	Missing test	Missing test
indices.open	🔴	17/18	17/18
indices.promote_data_stream	⚪	Missing test	Missing test
indices.put_alias	🔴	58/59	19/59
indices.put_data_lifecycle	⚪	Missing test	Missing test
indices.put_index_template	🔴	49/52	51/52
indices.put_mapping	🔴	72/76	75/76
indices.put_settings	🔴	53/57	56/57
indices.put_template	🔴	43/49	48/49
indices.recovery	🔴	8/9	8/9
indices.refresh	🔴	243/244	243/244
indices.reload_search_analyzers	🔴	1/2	1/2
indices.resolve_cluster	🔴	9/12	11/12
indices.resolve_index	🔴	5/6	5/6
indices.rollover	🔴	25/26	0/26
indices.segments	🔴	5/6	4/6
indices.shard_stores	🔴	4/5	3/5
indices.shrink	🔴	4/5	4/5
indices.simulate_index_template	🔴	5/7	4/7
indices.simulate_template	🔴	4/5	3/5
indices.split	🔴	10/11	10/11
indices.stats	🔴	102/103	30/102
indices.unfreeze	🔴	0/1	0/1
indices.update_aliases	🔴	25/26	6/26
indices.validate_query	🔴	6/7	6/7

You can validate these APIs yourself by using the make validate target.