[Linux] Bundled WPE is not truely self contained

### Is there an existing issue for this? - [x] I have searched the existing issues ### Current Behavior It appears that the bundled `libWPEWebKit` isn't self contained and still requires installed libraries to function this makes it hard/impossible to run the app on other distros that don't have wpe installed (or doesn't even host it like some ubuntu ones) could also make issues with isolated formats (like AppImage/Flatpak/Flake for NixOS) ### Expected Behavior Bundled WPE should be totally self contained so that it can run on systems without wpe installed ### Steps with code example to reproduce ### Steps with code example to reproduce 1. on Arch Linux (CachyOS) and using example app 2. install wpe `sudo pacman -S wpewebkit` 3. build linux `flutter build linux --release` 4. uninstall wpe `sudo pacman -R wpewebkit` 5. run app 6. error appears (check below) ### Stacktrace/Logs - Stacktrace/Logs ```sh ❯ ./my_app ** ERROR **: 20:42:45.599: Unable to spawn a new child process: Failed to spawn child process “/usr/lib/wpe-webkit-2.0/WPENetworkProcess” (No such file or directory) fish: Job 1, './my_app' terminated by signal SIGTRAP (Trace or breakpoint trap) ``` - here is ldd outputs (from [this fork](https://github.com/MSOB7YY/flutter_inappwebview) that tries to set rpath to app/lib instead of /usr/lib/ - (i notice that all paths are properly patched, yet it still refuses to run) - [ldd_app.txt](https://github.com/user-attachments/files/26192629/ldd_app.txt) - [ldd_libWPEWebKit.txt](https://github.com/user-attachments/files/26192630/ldd_libWPEWebKit.txt) - [ldd_WPENetworkProcess.txt](https://github.com/user-attachments/files/26192628/ldd_WPENetworkProcess.txt) - here is strings output (probably hardcoded paths in `libWPEWebKit`) ``` ❯ strings lib/libWPEWebKit-2.0.so.1.6.11 | grep "wpe-webkit-2.0" /usr/lib/wpe-webkit-2.0 /usr/share/wpe-webkit-2.0 /usr/lib/wpe-webkit-2.0/injected-bundle/ ``` ### Flutter version v3.41.4 ### Operating System, Device-specific and/or Tool Linux | CachyOS x86_64 | 6.19.7-1-cachyos (64-bit) KDE Plasma 6.6.2 ### Plugin version v6.2.0-beta.3 ### Additional information i tried many workarounds like setting `WEBKIT_EXEC_PATH` manually and others, still no luck. (worth noting that the package works perfectly when wpe stays installed, the issue appears only after uninstalling to emulate distros without wpe) let me know if u need more details, thanks for this awesome package! ### Self grab - [ ] I'm ready to work on this issue!