Add BATS test to verify spin plugins and templates are installed

[jandubois]

Passes BATS on CI: https://github.com/rancher-sandbox/rancher-desktop/actions/runs/9102407767

Additional manual BATS runs on Windows (with tunneling network, without using windows exes):

$ RD_USE_WINDOWS_EXE=1 RD_USE_NETWORKING_TUNNEL=1 ./bats-core/bin/bats -T tests/utils/*
spin.bats
   ===== utils/spin =====
 ✓ delete spin plugins and templates [336]                                                                     Install location:         system
   Resources path:           /mnt/c/Program Files/Rancher Desktop/resources/resources

   Container engine:         containerd
   Mount type:
   Using image allow list:   false
   Using Windows executables: true
   Using networking tunnel:  true

   Capturing logs:           false
   Tracing execution:        false
   Taking screenshots:       false
   Using ghcr.io images:     false
 ✓ confirm the spin directory is gone [134]
 ✓ start container engine with wasm support enabled [55349]
 ✓ plugins are installed [254]
 ✓ templates are installed [203]

5 tests, 0 failures in 81 seconds

$ RD_USE_NETWORKING_TUNNEL=1 ./bats-core/bin/bats -T tests/utils/*
spin.bats
   ===== utils/spin =====
 ✓ delete spin plugins and templates [246]                                                                     Install location:         system
   Resources path:           /mnt/c/Program Files/Rancher Desktop/resources/resources

   Container engine:         containerd
   Mount type:
   Using image allow list:   false
   Using Windows executables: false
   Using networking tunnel:  true

   Capturing logs:           false
   Tracing execution:        false
   Taking screenshots:       false
   Using ghcr.io images:     false
 ✓ confirm the spin directory is gone [81]
 ✓ start container engine with wasm support enabled [44931]
 ✓ plugins are installed [132]
 ✓ templates are installed [200]

5 tests, 0 failures in 65 seconds

[mook-as]

I don't think we need to include the log in the comment:

Suggested change

	// When running without wsl-exec the command cannot resolve DNS names:
	// # wsl-exec curl http://github.com
	// # curl http://github.com
	// curl: (6) Could not resolve host: github.com
	// wsl-exec is needed to correctly resolve DNS names.