Fix print filter action broken in Thunderbird 128+

[Copilot]

The "Print" filter action stopped working in Thunderbird 128+ (and broken in 152.0.1) due to window.ownerGlobal no longer providing access to PrintUtils, and the print.always_print_silent preference being removed in newer builds.

Changes

• content/filtaquilla.js
  • Replace window.ownerGlobal with Services.wm.getMostRecentWindow("mail:3pane") to reliably obtain PrintUtils in modern Thunderbird; window.ownerGlobal kept as fallback:

    // Before
    var { PrintUtils } = window.ownerGlobal;
    
    // After
    let mainWin = Services.wm.getMostRecentWindow("mail:3pane") || window.ownerGlobal;
    var { PrintUtils } = mainWin || {};

  • Wrap print.always_print_silent pref read/write in try/catch — preference was removed in newer Thunderbird; an unguarded getBoolPref throws and aborts the entire print path. Restore is skipped if the pref was never readable (null sentinel).

[RealRaven2000]

I found a better workaround (diodn't see your activity here):

var { PrintUtils } = globalThis;

why this works:

Firefox removed js access to ownderGlobal. globalThis works both in ESR140 (strict_min_ver) and ESR152 as tested by me.
https://phabricator.services.mozilla.com/D297183