fix: add comments for css hack

Author: dobrinyonkov

packages/fiori/src/themes/ShellBarV2.css

@@ -174,6 +174,10 @@
 }
 
 :host([show-search-field]) ::slotted([slot="searchField"]),
+/* Search field displays in full mode if there's not enough space in bar.
+Once in full screen mode the search field is rendered in another DOM. 
+To account for correct measurements in overflow, we should keep the min width 
+of the search field container in the bar even when the search is in full mode. */
 :host([show-full-width-search]) .ui5-shellbar-search-field-area {
 	min-width: var(--_ui5_shellbar_search_field_width);
 }