Revert backdrop utilization, handling clicks over modal (#36324)

* refactor(Modal.js): stop using backdrop class to handle clicks over modal

* Revert #35554 and backdrop callback usage
  Explanation: In order to bypass `.modal`, was applied a css rule `pointer-events:none` which caused the side effect, and user couldn't scroll "long content modals"

* Update .bundlewatch.config.json

Co-authored-by: Mark Otto <markd.otto@gmail.com>

.bundlewatch.config.json

@@ -34,7 +34,7 @@
     },
     {
       "path": "./dist/js/bootstrap.bundle.js",
-      "maxSize": "42.75 kB"
+      "maxSize": "43.0 kB"
     },
     {
       "path": "./dist/js/bootstrap.bundle.min.js",
@@ -42,7 +42,7 @@
     },
     {
       "path": "./dist/js/bootstrap.esm.js",
-      "maxSize": "27.5 kB"
+      "maxSize": "27.75 kB"
     },
     {
       "path": "./dist/js/bootstrap.esm.min.js",