refactor: remove unused builtinblock webpack entry points (openedx#35299

)

Most blocks built into edx-platform have a pair of webpack entry
points, like this:

* {BlockName}Display    # js for student+author+public views
* {BlockName}Editor     # js for studio view

Prior to a past build refactoring [1], these entry points were
defined in an auto-genered webpack config file. In order
to simplify the js build process, this config generation
step was removed and the new file webpack.builtinblocks.config.js
was checked directly into edx-platform.

However, during that refactoring, pointless entry
points were introduced for HtmlBlock subclasses
About, CourseInfo, and StaticTab, all of which
just use their superclass's JS.

[1] openedx#32481

webpack.builtinblocks.config.js

@@ -1,17 +1,5 @@
 module.exports = {
     entry: {
-        AboutBlockDisplay: [
-            './xmodule/js/src/xmodule.js',
-            './xmodule/js/src/html/display.js',
-            './xmodule/js/src/javascript_loader.js',
-            './xmodule/js/src/collapsible.js',
-            './xmodule/js/src/html/imageModal.js',
-            './xmodule/js/common_static/js/vendor/draggabilly.js'
-        ],
-        AboutBlockEditor: [
-            './xmodule/js/src/xmodule.js',
-            './xmodule/js/src/html/edit.js'
-        ],
         AnnotatableBlockDisplay: [
             './xmodule/js/src/xmodule.js',
             './xmodule/js/src/html/display.js',
@@ -33,18 +21,6 @@ module.exports = {
             './xmodule/js/src/xmodule.js',
             './xmodule/js/src/sequence/edit.js'
         ],
-        CourseInfoBlockDisplay: [
-            './xmodule/js/src/xmodule.js',
-            './xmodule/js/src/html/display.js',
-            './xmodule/js/src/javascript_loader.js',
-            './xmodule/js/src/collapsible.js',
-            './xmodule/js/src/html/imageModal.js',
-            './xmodule/js/common_static/js/vendor/draggabilly.js'
-        ],
-        CourseInfoBlockEditor: [
-            './xmodule/js/src/xmodule.js',
-            './xmodule/js/src/html/edit.js'
-        ],
         CustomTagBlockDisplay: './xmodule/js/src/xmodule.js',
         CustomTagBlockEditor: [
             './xmodule/js/src/xmodule.js',
@@ -104,18 +80,6 @@ module.exports = {
             './xmodule/js/src/xmodule.js',
             './xmodule/js/src/sequence/edit.js'
         ],
-        StaticTabBlockDisplay: [
-            './xmodule/js/src/xmodule.js',
-            './xmodule/js/src/html/display.js',
-            './xmodule/js/src/javascript_loader.js',
-            './xmodule/js/src/collapsible.js',
-            './xmodule/js/src/html/imageModal.js',
-            './xmodule/js/common_static/js/vendor/draggabilly.js'
-        ],
-        StaticTabBlockEditor: [
-            './xmodule/js/src/xmodule.js',
-            './xmodule/js/src/html/edit.js'
-        ],
         VideoBlockDisplay: [
             './xmodule/js/src/xmodule.js',
             './xmodule/js/src/video/10_main.js'