[Dialogs] Add TitleIcon snapshot tests.

Testing different combinations of configurations that affect the appearance of the title icon:
- title alignment.
- Long, wide & square images.
- Insets.
- LTR/RTL

## Issues
#9824 and #9545.

PiperOrigin-RevId: 302419683

Author: galiak11

components/Dialogs/tests/snapshot/MDCAlertControllerConfigurationsTests.m

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "long-image.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "long-image@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "long-image@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

components/Dialogs/tests/snapshot/resources/DialogsSnapshotTests.xcassets/long-image.imageset/Contents.json

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "square-image.jpg",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "square-image@2x.jpg",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "square-image@3x.jpg",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

components/Dialogs/tests/snapshot/resources/DialogsSnapshotTests.xcassets/long-image.imageset/long-image.png

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "wide-image.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "wide-image@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "wide-image@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}