Make width of profile tab conform to designs

src/settings/ProfileSettingsTab.module.css

@@ -14,6 +14,12 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+.content {
+  width: 100%;
+  max-width: 350px;
+  align-self: center;
+}
+
 .avatarFieldRow {
   justify-content: center;
 }

src/settings/ProfileSettingsTab.tsx

@@ -74,7 +74,7 @@ export function ProfileSettingsTab({ client }: Props) {
   );
 
   return (
-    <form onSubmit={onSubmit}>
+    <form onSubmit={onSubmit} className={styles.content}>
       <FieldRow className={styles.avatarFieldRow}>
         <AvatarInputField
           id="avatar"