settings: Improve UI for email changes.

This commit includes the following changes:
 - The email field is now a disabled text field.
 - An "Edit" (pencil) button is added next to the email
   field, which opens the change email modal.
 - The "Edit" button is not shown if the user doesn't
   have permission to edit their email.
 - When email changes are disabled, the "email changes are
   disabled" tooltip now appears over the email field, which
   previously appeared to the right of the email field.
 - Refactor `settings_org.test.cjs` to align with the changes
   of the added "Edit" button.

Fixes #31975.

web/src/tippyjs.ts

@@ -422,7 +422,7 @@ export function initialize(): void {
     });
 
     tippy.delegate("body", {
-        target: "#change_email_button_container.disabled_setting_tooltip",
+        target: "#email_field_container.disabled_setting_tooltip",
         content: $t({defaultMessage: "Email address changes are disabled in this organization."}),
         appendTo: () => document.body,
         onHidden(instance) {