Plugin does not use add_submenu_page() correctly

Notice: Function add_submenu_page was called incorrectly. The seventh parameter passed to add_submenu_page() should be numeric representing menu position.

Your code in this functions is wrong

	public function add_options_page(){
		global $admin_page_hooks;
		$plugin_slug_name = $this->get_plugin_slug();
		$plugin_title = $this->get_plugin_title();
		//add_options_page
		if ( empty ( $admin_page_hooks[$plugin_slug_name] ) ){
			add_options_page( 
				__( $plugin_title, $plugin_slug_name ),
				__( $plugin_title, $plugin_slug_name ),
				'manage_options',
				$plugin_slug_name,
				array( $this, 'itc_svg_upload_option_page' ),
				'dashicons-images-alt2',
			);
		}
	}

It should be

	public function add_options_page(){
		global $admin_page_hooks;
		$plugin_slug_name = $this->get_plugin_slug();
		$plugin_title = $this->get_plugin_title();
		//add_options_page
		if ( empty ( $admin_page_hooks[$plugin_slug_name] ) ){
			add_options_page( 
				__( $plugin_title, $plugin_slug_name ),
				__( $plugin_title, $plugin_slug_name ),
				'manage_options',
				$plugin_slug_name,
				array( $this, 'itc_svg_upload_option_page' )
			);
		}
	}

Or

	public function add_options_page(){
		global $admin_page_hooks;
		$plugin_slug_name = $this->get_plugin_slug();
		$plugin_title = $this->get_plugin_title();
		//add_options_page
		if ( empty ( $admin_page_hooks[$plugin_slug_name] ) ){
			add_options_page( 
				__( $plugin_title, $plugin_slug_name ),
				__( $plugin_title, $plugin_slug_name ),
				'manage_options',
				$plugin_slug_name,
				array( $this, 'itc_svg_upload_option_page' ),
				99,
			);
		}
	}

Please adjust