To disable install plugin from admin

add_action('init', 'remove_specific_admin_cap');
function remove_specific_admin_cap(){
 $user = wp_get_current_user();
 if( $user && isset($user->user_email)) {
    $role = get_role( 'administrator' );
    $role->remove_cap( 'install_plugins' );
    // $role->add_cap( 'install_plugins' ); to re enable install plugin feature
 }
}