Use consistent spacing and alphabetize dependabot.yml (#38012)

This uses consistent spacing for indentation. I'm not sure if it was
causing any issues but it has been a problem before (#36642). Also
reorder categories to be in alphabetical order.

Testing: No testing for Dependabot file.

Signed-off-by: Alex Touchet <26315797+atouchet@users.noreply.github.com>

.github/dependabot.yml

@@ -9,12 +9,6 @@ updates:
   - dependency-type: direct
   - dependency-type: indirect
   groups:
-    gstreamer-related:
-       patterns:
-         - "gio*"
-         - "glib*"
-         - "gobject*"
-         - "gstreamer*"
     egui-related:
       patterns:
         - "ecolor"
@@ -24,16 +18,22 @@ updates:
         - "emath"
         - "epaint"
         - "epaint_default_fonts"
+    gstreamer-related:
+      patterns:
+        - "gio*"
+        - "glib*"
+        - "gobject*"
+        - "gstreamer*"
     napi-ohos-related:
       patterns:
         - "napi-ohos*"
         - "napi-*-ohos*"
-    servo-media-related:
-      patterns:
-        - "servo-media*"
     objc2-related:
       patterns:
         - "objc2*"
+    servo-media-related:
+      patterns:
+        - "servo-media*"
   ignore:
   # Ignore all stylo crates as their upgrades are coordinated via companion PRs.
   - dependency-name: selectors