Improve file handling of special characters in WebIDE

What does this MR do?

This fixes #54376 (closed) by escaping the hash characters in the Web IDE.

If a hash (#) was added to a file name it would crash the Web IDE.

What are the relevant issue numbers?

#54376 (closed)

Does this MR meet the acceptance criteria?

Since this is my first MR, I may need help in crafting it. I have put my comments in italics where I think things are at.

• Changelog entry added, if necessary after reading the guide, this didnt look necessary
• Documentation created/updated via this MR no change in functionality
• Documentation reviewed by technical writer or follow-up review issue created N/A
• Tests added for this feature/bug Should I add tests for this bug? If so I can.
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer

app/assets/javascripts/ide/lib/files.js

 import { viewerInformationForPath } from '~/vue_shared/components/content_viewer/lib/viewer_utils';
 import { decorateData, sortTree } from '../stores/utils';
 
+const escapeFileUrl = fileUrl => encodeURIComponent(fileUrl).replace(/%2F/g, '/');
+
 export const splitParent = path => {
   const idx = path.lastIndexOf('/');
 
@@ -45,7 +47,7 @@ export const decorateFiles = ({
       id: path,
       name,
       path,
-      url: `/${projectId}/tree/${branchId}/-/${path}/`,
+      url: `/${projectId}/tree/${branchId}/-/${escapeFileUrl(path)}/`,
       type: 'tree',
       parentTreeUrl: parentFolder ? parentFolder.url : `/${projectId}/tree/${branchId}/`,
       tempFile,
@@ -81,7 +83,7 @@ export const decorateFiles = ({
         id: path,
         name,
         path,
-        url: `/${projectId}/blob/${branchId}/-/${path}`,
+        url: `/${projectId}/blob/${branchId}/-/${escapeFileUrl(path)}`,
         type: 'blob',
         parentTreeUrl: fileFolder ? fileFolder.url : `/${projectId}/blob/${branchId}`,
         tempFile,