Remove `gulp-babel` package (#10437)

This has not been used in some time. The last import was removed in
the PR #4712

package.json

@@ -234,7 +234,6 @@
     "get-port": "^5.1.0",
     "gulp": "^4.0.2",
     "gulp-autoprefixer": "^5.0.0",
-    "gulp-babel": "^8.0.0",
     "gulp-imagemin": "^6.1.0",
     "gulp-livereload": "4.0.0",
     "gulp-rename": "^2.0.0",

yarn.lock

@@ -12512,16 +12512,6 @@ gulp-autoprefixer@^5.0.0:
     through2 "^2.0.0"
     vinyl-sourcemaps-apply "^0.2.0"
 
-gulp-babel@^8.0.0:
-  version "8.0.0"
-  resolved "https://registry.yarnpkg.com/gulp-babel/-/gulp-babel-8.0.0.tgz#e0da96f4f2ec4a88dd3a3030f476e38ab2126d87"
-  integrity sha512-oomaIqDXxFkg7lbpBou/gnUkX51/Y/M2ZfSjL2hdqXTAlSWZcgZtd2o0cOH0r/eE8LWD0+Q/PsLsr2DKOoqToQ==
-  dependencies:
-    plugin-error "^1.0.1"
-    replace-ext "^1.0.0"
-    through2 "^2.0.0"
-    vinyl-sourcemaps-apply "^0.2.0"
-
 gulp-cli@^2.2.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/gulp-cli/-/gulp-cli-2.3.0.tgz#ec0d380e29e52aa45e47977f0d32e18fd161122f"