chore(): fix package dependencies for screenshot-tool app (#6276)

Recently some utilities have been moved from the Material package to the CDK package. At this point Material added the CDK as a peer dependency.

The screenshot-test application uses the most recent (released) Angular Material version (due to the caret in the semver expression) but doesn't have a dependency on the CDK yet.

This commit adds the CDK as a dependency and also switches Material and the CDK to the latest build artifcats on GitHub (as same as for the dashboard).

tools/screenshot-test/firebase.json

@@ -0,0 +1,11 @@
+{
+  "hosting": {
+    "public": "dist",
+    "rewrites": [
+      {
+        "source": "**",
+        "destination": "/index.html"
+      }
+    ]
+  }
+}

tools/screenshot-test/package.json

@@ -10,13 +10,14 @@
   "private": true,
   "dependencies": {
     "@angular/animations": "^4.0.2",
+    "@angular/cdk": "angular/cdk-builds",
     "@angular/common": "^4.0.0",
     "@angular/compiler": "^4.0.0",
     "@angular/compiler-cli": "^4.0.0",
     "@angular/core": "^4.0.0",
     "@angular/forms": "^4.0.0",
     "@angular/http": "^4.0.0",
-    "@angular/material": "^2.0.0-beta.3",
+    "@angular/material": "angular/material2-builds",
     "@angular/platform-browser": "^4.0.0",
     "@angular/platform-browser-dynamic": "^4.0.0",
     "@angular/router": "^4.0.0",