Enable the unicorn/prefer-optional-catch-binding ESLint plugin rule

According to MDN this format is available in all browsers/environments that we currently support, see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/try...catch#browser_compatibility

Please also see https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/prefer-optional-catch-binding.md

web/pdf_presentation_mode.js

@@ -101,7 +101,7 @@ class PDFPresentationMode {
       await promise;
       pdfViewer.focus(); // Fixes bug 1787456.
       return true;
-    } catch (reason) {
+    } catch {
       this.#removeFullscreenChangeListeners();
       this.#notifyStateChange(PresentationModeState.NORMAL);
     }