Fix errors due to icon to codicon rename in VSCode (#7837)

Found numerous errors where icons weren't rendering correctly.
- Anything that's an action must have CSS using "codicon" not "icon"
since VSCode sets the "codicon" class automatically.
This affected Agent view in particular, but also:
  - acounts view
  - new tab view in dashboard
 - many more
- Anything referencing the common-icons.css icons needed updating.
This hid help tooltip text in FormContainer UI for example.
- Finally I tried to convert all references from icon -> codicon,
even when the CSS was technically correct. This was done
for maintainability reasons - from now on always add codicon.

Fixes #7827

src/sql/workbench/browser/modelComponents/formContainer.component.ts

@@ -52,7 +52,7 @@ class FormItem {
 					<ng-container *ngIf="isHorizontal(item)">
 						<div *ngIf="hasItemTitle(item)" class="form-cell form-cell-title" [style.font-size]="getItemTitleFontSize(item)" [ngClass]="{'form-group-item': isInGroup(item)}">
 							{{getItemTitle(item)}}<span class="form-required" *ngIf="isItemRequired(item)">*</span>
-							<span class="icon help form-info" *ngIf="itemHasInfo(item)" [title]="getItemInfo(item)"></span>
+							<span class="codicon help form-info" *ngIf="itemHasInfo(item)" [title]="getItemInfo(item)"></span>
 						</div>
 						<div class="form-cell">
 							<div class="form-component-container">
@@ -72,7 +72,7 @@ class FormItem {
 					<div class="form-vertical-container" *ngIf="isVertical(item)" [style.height]="getRowHeight(item)" [ngClass]="{'form-group-item': isInGroup(item)}">
 						<div class="form-item-row" [style.font-size]="getItemTitleFontSize(item)">
 							{{getItemTitle(item)}}<span class="form-required" *ngIf="isItemRequired(item)">*</span>
-							<span class="icon help form-info" *ngIf="itemHasInfo(item)" [title]="getItemInfo(item)"></span>
+							<span class="codicon help form-info" *ngIf="itemHasInfo(item)" [title]="getItemInfo(item)"></span>
 						</div>
 						<div class="form-item-row" [style.width]="getComponentWidth(item)" [style.height]="getRowHeight(item)">
 							<model-component-wrapper [descriptor]="item.descriptor" [modelStore]="modelStore" [style.width]="getComponentWidth(item)" [style.height]="getRowHeight(item)">