umu_run: remove winetricks environment variables

- Currently, winetricks verbs are being applied to the wine prefix by executing the winetricks script as an executable for Proton. For some reason, this results in system calls failing for container binaries such as grep and sed, which are required by winetricks for parsing. Here's an example of grep's coredump:

Stack trace of thread 52329:
0  0x000070003275383b n/a (/lib/ld-linux-x86-64.so.2 + 0x2183b)
1  0x000070003274e0f8 n/a (/lib/ld-linux-x86-64.so.2 + 0x1c0f8)
2  0x000070003274f9be n/a (/lib/ld-linux-x86-64.so.2 + 0x1d9be)
3  0x000070003274e748 n/a (/lib/ld-linux-x86-64.so.2 + 0x1c748)
ELF object binary architecture: AMD x86-64

While this doesn't appear to impact the application of winetricks verbs to the prefix nor has there been reports of this problem yet, as a precaution, we should set these environment variables from the proton script and replicate protonfixes' execution. As a result, there should be no more coredumps except from wine64-preloader, which should be normal, and the launcher will only guard against valid winetricks verbs

umu/umu_run.py

@@ -296,20 +296,6 @@ def set_env(
 
     # Winetricks
     if env.get("EXE", "").endswith("winetricks"):
-        # Proton directory with the last segment being subdirectory containing
-        # the Proton libraries and binaries. In upstream Proton 9 the subdir
-        # is 'files', while in other versions it may be 'dist'.
-        proton_dist: str = (
-            f"{env['PROTONPATH']}/files"
-            if Path(env["PROTONPATH"], "files").is_dir()
-            else f"{env['PROTONPATH']}/dist"
-        )
-
-        env["WINE"] = f"{proton_dist}/bin/wine"
-        env["WINELOADER"] = env["WINE"]
-        env["WINESERVER"] = f"{proton_dist}/bin/wineserver"
-        env["WINETRICKS_LATEST_VERSION_CHECK"] = "disabled"
-        env["LD_PRELOAD"] = ""
         env["WINETRICKS_SUPER_QUIET"] = (
             "" if os.environ.get("UMU_LOG") == "debug" else "1"
         )