Merge branch 'flash-cherry-pick-error' into 'master'

Prevent flash alert text from being obscured when container is fluid

Fixes [a regression](https://gitlab.com/gitlab-org/gitlab-ce/commit/a2af7790) that causes the text within server-initiated flash *alerts* (not flash *notices*) to be obscured when `.container-fluid` is applied. It was reported in relation to a cherry-picking flash alert, but the problem occurs with all server-initiated flash alerts contained by a fluid container.

Note that as part of this fix, I combined some duplicate code and removed `.flash-text` & `.content-wrapper` selectors as they didn't seem to be necessary.

I manually tested JS-initiated Flash alerts to make sure this doesn't affect their appearance. I also grepped around for anything else that might depend on these styles. Everything checked out. But... can *you* see something this is going to break?

Affected users can't read flash alerts.

https://gitlab.com/gitlab-org/gitlab-ce/issues/22915

See merge request !6694
Signed-off-by: Rémy Coutable <remy@rymai.me>

CHANGELOG

@@ -4,6 +4,7 @@ v 8.12.7
   - Prevent running GfmAutocomplete setup for each diff note. !6569
   - Fix Long commit messages overflow viewport in file tree. !6573
   - Use gitlab-markup gem instead of github-markup to fix `.rst` file rendering. !6659
+  - Prevent flash alert text from being obscured when container is fluid. !6694
 
 v 8.12.6
   - Update mailroom to 0.8.1 in Gemfile.lock  !6814

app/assets/stylesheets/framework/flash.scss

@@ -20,7 +20,8 @@
   .flash-notice, .flash-alert {
     border-radius: $border-radius-default;
 
-    .container-fluid.container-limited.flash-text {
+    .container-fluid,
+    .container-fluid.container-limited {
       background: transparent;
     }
   }