MDL-64172 block_myoverview: use .text-primary to colour star icons

Using the .text-primary class allows colour to be overridden easily
This will back the dashboard icons look consistent with the messaging icons.

blocks/myoverview/templates/course-action-menu.mustache

@@ -41,7 +41,7 @@
             data-course-id="{{id}}"
             aria-controls="favorite-icon-{{ id }}"
             >
-            {{#pix}} i/star, core, {{#str}} favourites, block_myoverview {{/str}} {{/pix}}
+            <span class="text-primary">{{#pix}} i/star, core, {{#str}} favourites, block_myoverview {{/str}} {{/pix}}</span>
             {{#str}} addtofavourites, block_myoverview {{/str}}
             <div class="sr-only">
                 {{#str}} aria:addtofavourites, block_myoverview {{/str}} {{{fullname}}}

course/templates/favouriteicon.mustache

@@ -30,7 +30,7 @@
     data-course-id="{{id}}"
     >
     <span
-        class="{{^isfavourite}}hidden{{/isfavourite}}"
+        class="text-primary {{^isfavourite}}hidden{{/isfavourite}}"
         data-region="is-favourite"
         aria-hidden="{{^isfavourite}}true{{/isfavourite}}{{#isfavourite}}false{{/isfavourite}}"
         >

theme/boost/scss/moodle/blocks.scss

@@ -94,9 +94,6 @@ $card-gutter : $card-deck-margin * 2;
     }
     .icon {
         margin-right: 0;
-        &.fa-star {
-            color: $blue;
-        }
     }
     .card .coursemenubtn {
         margin-top: -0.5rem;

theme/boost/style/moodle.css

@@ -11224,8 +11224,6 @@ div.editor_atto_toolbar button .icon {
 
 .block .block-cards .icon {
   margin-right: 0; }
-  .block .block-cards .icon.fa-star {
-    color: #1177d1; }
 
 .block .block-cards .card .coursemenubtn, .block .block-cards #page-enrol-users #filterform .coursemenubtn, #page-enrol-users .block .block-cards #filterform .coursemenubtn, .block .block-cards .que .history .coursemenubtn, .que .block .block-cards .history .coursemenubtn, .block .block-cards .userprofile .profile_tree section .coursemenubtn, .userprofile .profile_tree .block .block-cards section .coursemenubtn, .block .block-cards .groupinfobox .coursemenubtn, .block .block-cards .well .coursemenubtn {
   margin-top: -0.5rem; }