yazi: fix unintended recursive calls

Use `command` (POSIX) and `^` (Nushell) to prevent recursive function
calls when `cfg.shellWrapperName` is set to "yazi".

Previously, if `cfg.shellWrapperName` was set to "yazi", the invocation
of `yazi` within the shell integration function triggered the function
itself instead of the binary. This name conflict prevents users from
using the binary name as-is when shell integration is enabled.

Hence, fix this by using shell-specific mechanisms to target the
underlying executable, bypassing any name collisions.

This aligns with the official documentation:
- 2c839b37c8/docs/quick-start.md (L29)
- 2c839b37c8/docs/quick-start.md (L56)

tests/modules/programs/yazi/bash-integration-enabled.nix

@@ -10,7 +10,7 @@
     assertFileExists home-files/.bashrc
     assertFileContains home-files/.bashrc 'function yy() {'
     assertFileContains home-files/.bashrc 'local tmp="$(mktemp -t "yazi-cwd.XXXXX")"'
-    assertFileContains home-files/.bashrc 'yazi "$@" --cwd-file="$tmp"'
+    assertFileContains home-files/.bashrc 'command yazi "$@" --cwd-file="$tmp"'
     assertFileContains home-files/.bashrc 'if cwd="$(<"$tmp")" && [ -n "$cwd" ] && [ "$cwd" != "$PWD" ]; then'
     assertFileContains home-files/.bashrc 'builtin cd -- "$cwd"'
     assertFileContains home-files/.bashrc 'rm -f -- "$tmp"'