based on pgomulka:compat/delete_update #58246

CompatRestIT. test {yaml=indices.get_field_mapping/30_missing_type/Raise 404 when type doesn't exist}
because of that change (custom type to _doc) a test that was expecting 404 for a type that did not exist, passes now as the logic is trying to fetch for _doc (any type that exist on that index will be good).

CompatRestIT. test {yaml=indices.get_mapping/11_basic_with_types/Get /{index}/_mapping with empty mappings}
this is because I can't tell if the mapping contained a type or not when fetching a mapping.

CompatRestIT. test {yaml=indices.get_mapping/20_missing_type/Existent and non-existent type returns 404 and the existing type}
CompatRestIT. test {yaml=indices.get_mapping/20_missing_type/Existent and non-existent types returns 404 and the existing type}
CompatRestIT. test {yaml=indices.get_mapping/20_missing_type/No type matching pattern returns 404}
CompatRestIT. test {yaml=indices.get_mapping/20_missing_type/Non-existent type returns 404}
failing - (not returning 404) - because type is always found (defaulted to _doc)

CompatRestIT. test {yaml=indices.get_mapping/20_missing_type/Type missing when no types exist}
CompatRestIT. test {yaml=indices.get_mapping/61_empty_with_types/Check empty mapping when getting all mappings via /_mapping}
CompatRestIT. test {yaml=indices.get_template/11_basic_with_types/Get template with no mappings}
CompatRestIT. test {yaml=indices.get_template/11_basic_with_types/Get template}
CompatRestIT. test {yaml=indices.put_mapping/20_mix_typeless_typeful/PUT mapping with _doc on an index that has types}
CompatRestIT. test {yaml=indices.put_mapping/20_mix_typeless_typeful/PUT mapping with typeless API on an index that has types}
#47364
#41676

…get field mappings (#71721)

Implements a V7 compatible typed endpoints for REST put and get mapping endpoints. Also for Get Field Mappings endpoints.
retrofits the REST layer change removed in #41676

relates main meta issue #51816
relates types removal issue #54160