fix(angular): Exclude template block grammars in CSS and JS contexts

This commit ensures the Angular template block syntax highlighting does
not apply in in the HTML language where it has transitioned to embedded
`css` or `js` (i.e. in `script` tags).

grammars/angular/syntaxes/template-blocks.json

@@ -1,6 +1,6 @@
 {
 	"scopeName": "template.blocks.ng",
-	"injectionSelector": "L:text.html -comment -expression.ng -meta.tag",
+	"injectionSelector": "L:text.html -comment -expression.ng -meta.tag -source.css -source.js",
 	"patterns": [
 		{
 			"include": "#block"