Make clearer the distinction between "storage-mode" and "delta-mode" usage of *Settings objects

- Storage mode: for use in `self._settings`. All fields should be specified, i.e. should not be `NOT_GIVEN`.
- Delta mode: for use in `*UpdateSettingsFrame`.

In service of this, this commit:
- Adds a runtime check that all fields are specified in storage mode
- Updates all services to specify all fields in stored settings
- Updates all services to no longer check for `is_given` in stored settings (not necessary anymore)
- Updates relevant docstrings
- Renames `update` to `delta` in `*UpdateSettingsFrame`
- Updates community integrations guide

changelog/3714.added.md

@@ -12,7 +12,7 @@
 
   ```python
   await task.queue_frame(
-      STTUpdateSettingsFrame(update=DeepgramSTTSettings(language=Language.ES))
+      STTUpdateSettingsFrame(delta=DeepgramSTTSettings(language=Language.ES))
   )
   ```
 

changelog/3714.deprecated.2.md

@@ -1 +1 @@
-- Dict-based `*UpdateSettingsFrame(settings={...})` is deprecated in favor of passing typed settings delta objects with `*UpdateSettingsFrame(update={...})`.
+- Dict-based `*UpdateSettingsFrame(settings={...})` is deprecated in favor of passing typed settings delta objects with `*UpdateSettingsFrame(delta={...})`.