MM-53814 - Updating contrast for accessibility (#24381)

* Updating contrast for accessiblity

* Updating accessbility

* Updating accessiblity for icons

* Updating header icons

* Updating text opacity

* Updating icons and text

* Updating sidebar left

* Upadating icon in system console

* Updating global header

* Updating channel list

* Updating tests and fixing conflicts

* Updating filter css

* Updating css

* Updating epehemeral message contrast

* Updating icon with 64 opacity

* Updating test

* Updating confirm license removal csss

* Updating unintended files

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Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/cloud_invoice_preview/cloud_invoice_preview.scss

@@ -16,7 +16,7 @@
         .close {
             margin-top: auto;
             margin-bottom: auto;
-            color: rgba(#3f4350, 0.56) !important;
+            color: rgba(#3f4350, 0.75) !important;
         }
 
         .modal-title {
@@ -29,7 +29,7 @@
 
         .subtitle {
             margin-top: 10px;
-            color: rgba(#3d3c40, 0.72);
+            color: rgba(#3d3c40, 0.75);
             font-family: 'Metropolis';
             font-size: 14px;
             font-style: normal;