PLT-6905 - Updating channel header design (#6789)

* PLT-6905 - Updating channel header design

* Updating border-radius

* Updating radius for wide icons

* Updating trigger for overlay

* Updating UI for channel header

* Updating channel header sizing

* Updating channel header css

* Updating sidebar css

* Updating status icons

* Adjusting border

* Updating comment

* Removing type from status icon

* Fixing UI issues for the channel header/sidebar

* make "Add a channel description" open the channel header modal

* Updating status and opacity

* Updating stauts icon positioning

* Updating description and heading size

* Updating UI changes

* Updating UI changes

* add a focused class to the parent div .search__form and then remove when hover away

* Fix active state for pinned posts icon

* Updating UI changes

* Update channel header text

webapp/sass/components/_inputs.scss

@@ -45,3 +45,23 @@ input {
         margin-top: 3px;
     }
 }
+
+::-webkit-input-placeholder { /* Chrome/Opera/Safari */
+    color: inherit;
+    opacity: 0.5;
+}
+
+::-moz-placeholder { /* Firefox 19+ */
+    color: inherit;
+    opacity: 0.5;
+}
+
+:-ms-input-placeholder { /* IE 10+ */
+    color: inherit;
+    opacity: 0.5;
+}
+
+:-moz-placeholder { /* Firefox 18- */
+    color: inherit;
+    opacity: 0.5;
+}