Fix conversion of hex color strings in project converter

[ericliu206]

fixes #73633

[ericliu206]

This appears to fix the issue, however, I am not sure if this is the best way to organize the code. Any suggestions will be appreciated. :)

[Maran23]

Can you also add tests? (test_conversion_gdscript_builtin).
Also you need to rebase the branch. :)

[YuriSizov]

Sorry for the wait. So I checked this again and realized my suggestion was rather poor, as it would incorrectly convert your normal 6-character long hex colors.

Test set

Color("#dede")
Color("dede")
Color("#7e4e")
Color("8e0d")
Color("#bcbcbc")
Color("fefefe")
Color("#11dd33aa")
Color("11dd33aa")
Color("#9d9g9e")
Color("abch")
Color("#deded")
Color("0909909")
Color("123456789")

So I went ahead and updated your PR on your behalf, adding more tests to catch these cases and splitting the operation into two passes: one explicitly for 4 characters and another explicitly for 8 characters.

[akien-mga]

Thanks! And congrats for your first merged Godot contribution 🎉

[YuriSizov]

Cherry-picked for 4.1.3.