[BUG] Incorrect error message when calling the libWrapper API before the libWrapper.Ready hook

[ruipin]

Describe the bug
When trying to register a wrapper before the libWrapper.Ready hook, if this happens before game.modules is available, libWrapper will try to construct an error message and fail with an error message like:

[Detected 2 packages: lib-wrapper, XYZ]
    at PackageInfo.get exists [as exists] (libWrapper-package_info.js:328)
    at de (libWrapper-api.js:273)
    at Function.🎁register [as register] (libWrapper-api.js:471)
    at XYZ.js:5

To Reproduce
Steps to reproduce the behavior:

1. Write a module which calls libWrapper.register before the libWrapper.Ready hook fires.
2. Enter a world and enable the module.
3. Refresh.
4. See the error in the JS console.

Expected behavior
libWrapper should give the error Not allowed to register wrappers before the 'libWrapper.Ready' hook fires instead.

Technical Details (please complete the following information):

• LibWrapper Version: 1.12.8.0 (and older)
• FoundryVTT Version: Any
• Browser & Version: Any

Additional context
This seems to be caused by api.js:475, which throws a LibWrapperPackageError exception when libWrapper isn't ready yet, which will trigger a PackageInfo::exists call during the error message construction.

This PackageInfo::exists method does not correctly handle the case where game.modules is undefined.

[ruipin]

Fixed by v1.12.9.0. Closing.