Member avatars without canvas (#9990)

* Strict typechecking fixes for Base/Member/Avatar

Update the core avatar files to pass `--strict --noImplicitAny` typechecks.

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>

* Add tests for Base/Member/Avatar

More thoroughly test the core avatar files. Not necessarily the most thorough,
but an improvement.

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>

* Extract TextAvatar from BaseAvatar

Extracted the fallback/textual avatar into its own component.

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>

* Use standard HTML for non-image avatars

Firefox users with `resistFingerprinting` enabled were seeing random noise
for rooms and users without avatars. There's no real reason to use data
URLs to present flat colors.

This converts non-image avatars to inline blocks with background colors.

See https://github.com/vector-im/element-web/issues/23936

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>

* Have pills use solid backgrounds rather than colored images

Similar to room and member avatars, pills now use colored pseudo-elements
rather than background images.

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>

---------

Signed-off-by: Clark Fischer <clark.fischer@gmail.com>
Co-authored-by: Andy Balaam <andy.balaam@matrix.org>

src/dispatcher/payloads/ViewUserPayload.ts

@@ -28,4 +28,11 @@ export interface ViewUserPayload extends ActionPayload {
      * should be shown (hide whichever relevant components).
      */
     member?: RoomMember | User;
+
+    /**
+     * Should this event be pushed as a card into the right panel?
+     *
+     * @see RightPanelStore#pushCard
+     */
+    push?: boolean;
 }