UndertaleModTool Clean up some warnings and errors

Description

PR checks have been plagued with tons of warning messages at the end (at least with GitHub's beta "Unchanged files with check annotations"), so this PR aims to get rid of a bunch of them.

Caveats

WebClient was replaced with HttpClient, so there may be slight behavioral differences. I did test the updater, though, and it functioned fine.

Some files now have #pragma directives to disable cross-platform compatibility warnings, but I limited this specifically to GUI, which is already Windows-only, at least as it stands.

Notes

~~Starting this as a draft to make sure the warnings no longer show up in the build pipeline.~~ This seems to have worked.

Aug 27 '24 16:08 colinator27

Download the artifacts for this pull request here:

GUI:

CLI:

Aug 27 '24 16:08 github-actions[bot]

Reviews seem pretty much resolved, and I want to take advantage of the warnings when merging the next batch of PRs, so I'll go ahead and merge this for now. For certain style things, we can certainly change them later.

Jan 20 '25 18:01 colinator27