Intent to ship: Promise.try

[Daniel Minor]

As of Firefox 134, I intend to turn the `Promise.try` proposal implementation on by default on all platforms. It has been developed behind the `javascript.options.experimental.promise_try` preference. The proposal advanced to Stage 4 of the TC39 process at the October 2024 Plenary, and has already been shipped by Chrome and Safari.

Bug to turn on by default: https://bugzilla.mozilla.org/show_bug.cgi?id=1917879 is the bug to enable.

Standard: https://github.com/tc39/proposal-promise-try

Daniel