Fix variable names

Related to:
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2565
- https://github.com/spantaleev/matrix-docker-ansible-deploy/pull/2566

roles/custom/matrix-dendrite/defaults/main.yml

@@ -213,8 +213,8 @@ matrix_dendrite_userapi_auto_join_rooms: []
 matrix_dendrite_report_stats: false
 
 # Contorls whether thumbnails for media content are generated dynamically
-matrix_dendrite_mediaapi_dynamic_thumbnails: false
-matrix_dendrite_mediaapi_max_thumbnail_generators: 10
+matrix_dendrite_media_api_dynamic_thumbnails: false
+matrix_dendrite_media_api_max_thumbnail_generators: 10
 
 # Controls whether the full-text search engine is enabled
-matrix_dendrite_syncapi_search_enabled: false
+matrix_dendrite_sync_api_search_enabled: false

roles/custom/matrix-dendrite/templates/dendrite/dendrite.yaml.j2

@@ -293,10 +293,10 @@ media_api:
   max_file_size_bytes: {{ matrix_dendrite_max_file_size_bytes|to_json }}
 
   # Whether to dynamically generate thumbnails if needed.
-  dynamic_thumbnails: {{ matrix_dendrite_mediaapi_dynamic_thumbnails|to_json }}
+  dynamic_thumbnails: {{ matrix_dendrite_media_api_dynamic_thumbnails|to_json }}
 
   # The maximum number of simultaneous thumbnail generators to run.
-  max_thumbnail_generators: {{ matrix_dendrite_mediaapi_max_thumbnails_generators|to_json }}
+  max_thumbnail_generators: {{ matrix_dendrite_media_api_max_thumbnails_generators|to_json }}
 
   # A list of thumbnail sizes to be generated for media content.
   thumbnail_sizes:
@@ -355,7 +355,7 @@ sync_api:
   # Configuration for the full-text search engine.
   search:
     # Whether or not search is enabled.
-    enabled: {{ matrix_dendrite_syncapi_search_enabled|to_json }}
+    enabled: {{ matrix_dendrite_sync_api_search_enabled|to_json }}
     # The path where the search index will be created in.
     index_path: "/matrix-media-store-parent/searchindex"
     # The language most likely to be used on the server - used when indexing, to