[MM-61629]: Remove tabIndex (#29744)

webapp/channels/src/components/channel_notifications_modal/__snapshots__/channel_notifications_modal.test.tsx.snap

@@ -36,7 +36,6 @@ Object {
               <h1
                 class="mm-modal-header__title"
                 id="mm-modal-header-channelNotificationModalLabel"
-                tabindex="0"
               >
                 Notification Preferences
               </h1>
@@ -456,7 +455,6 @@ Object {
               <h1
                 class="mm-modal-header__title"
                 id="mm-modal-header-channelNotificationModalLabel"
-                tabindex="0"
               >
                 Notification Preferences
               </h1>
@@ -1014,7 +1012,6 @@ Object {
               <h1
                 class="mm-modal-header__title"
                 id="mm-modal-header-channelNotificationModalLabel"
-                tabindex="0"
               >
                 Notification Preferences
               </h1>
@@ -1319,7 +1316,6 @@ Object {
               <h1
                 class="mm-modal-header__title"
                 id="mm-modal-header-channelNotificationModalLabel"
-                tabindex="0"
               >
                 Notification Preferences
               </h1>
@@ -1820,7 +1816,6 @@ Object {
               <h1
                 class="mm-modal-header__title"
                 id="mm-modal-header-channelNotificationModalLabel"
-                tabindex="0"
               >
                 Notification Preferences
               </h1>
@@ -2321,7 +2316,6 @@ Object {
               <h1
                 class="mm-modal-header__title"
                 id="mm-modal-header-channelNotificationModalLabel"
-                tabindex="0"
               >
                 Notification Preferences
               </h1>

webapp/channels/src/components/widgets/modals/components/modal_header.tsx

@@ -19,7 +19,6 @@ function ModalHeader({id, title, subtitle, handleClose}: Props) {
             <h1
                 id={`mm-modal-header-${id}`}
                 className='mm-modal-header__title'
-                tabIndex={0}
             >
                 {title}
             </h1>