Stringify relevant properties

[Anaethelion]

While hardening the JSON decode tests for the Go client I've stumbled upon several instance of integer and one boolean that can also be a string in some instances.

[cla-checker-service]

💚 CLA has been signed

[github-actions]

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

API	Status	Request	Response
indices.add_block	🟢	2/2	2/2
indices.analyze	🟢	20/20	20/20
indices.clear_cache	🟢	4/4	4/4
indices.clone	🟢	4/4	4/4
indices.close	🟢	40/40	40/40
indices.create_data_stream	🟢	25/25	25/25
indices.create	🔴	672/675	675/675
indices.data_streams_stats	🟢	4/4	4/4
indices.delete_alias	🟢	15/15	15/15
indices.delete_data_lifecycle	🟠	Missing type	Missing type
indices.delete_data_stream	🟢	27/27	27/27
indices.delete_index_template	🟢	1/1	1/1
indices.delete_template	🟢	9/9	9/9
indices.delete	🟢	103/103	103/103
indices.disk_usage	🟢	3/3	3/3
indices.downsample	🟢	1/1	1/1
indices.exists_alias	🟢	36/36	36/36
indices.exists_index_template	⚪	Missing test	Missing test
indices.exists_template	🟢	15/15	15/15
indices.exists	🟢	39/39	39/39
indices.explain_data_lifecycle	🟠	Missing type	Missing type
indices.field_usage_stats	🟢	4/4	4/4
indices.flush	🟢	9/9	9/9
indices.forcemerge	🔴	4/4	3/4
indices.get_alias	🔴	82/82	70/82
indices.get_data_lifecycle	🟠	Missing type	Missing type
indices.get_data_stream	🟢	12/12	12/12
indices.get_field_mapping	🔴	15/15	14/15
indices.get_index_template	🔴	16/16	14/16
indices.get_mapping	🔴	54/54	53/54
indices.get_settings	🔴	54/54	52/54
indices.get_template	🟢	30/30	30/30
indices.get	🟢	52/52	52/52
indices.migrate_to_data_stream	⚪	Missing test	Missing test
indices.modify_data_stream	⚪	Missing test	Missing test
indices.open	🟢	16/16	16/16
indices.promote_data_stream	⚪	Missing test	Missing test
indices.put_alias	🟢	53/53	53/53
indices.put_data_lifecycle	🟠	Missing type	Missing type
indices.put_index_template	🔴	37/39	39/39
indices.put_mapping	🔴	72/73	73/73
indices.put_settings	🔴	51/53	53/53
indices.put_template	🔴	40/46	46/46
indices.recovery	🟢	8/8	8/8
indices.refresh	🟢	182/182	182/182
indices.reload_search_analyzers	🟢	2/2	2/2
indices.resolve_index	🟢	6/6	6/6
indices.rollover	🟢	26/26	26/26
indices.segments	🔴	6/6	5/6
indices.shard_stores	🔴	5/5	4/5
indices.shrink	🟢	4/4	4/4
indices.simulate_index_template	🟢	6/6	6/6
indices.simulate_template	🟢	4/4	4/4
indices.split	🟢	11/11	11/11
indices.stats	🟢	85/85	84/84
indices.unfreeze	🟢	1/1	1/1
indices.update_aliases	🟢	22/22	22/22
indices.validate_query	🟢	7/7	7/7

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

[swallez]

LGTM