fix: add doctor diagnostic tests for v2 crypto

[shetzel]

What does this PR do?

REQUIRES: forcedotcom/sfdx-core#810

Adds doctor diagnostic tests for v2 crypto.

What issues does this PR fix or reference?

@W-14999859@

[cristiand391]

QA notes:

with sf v2.33.3

v2 crypto + generic unix keychain

✅ CLI supports v2 warn, CLI using stable v2 crypto fails
two 3rd party plugins use old sfdx-core, suggestions mention to go back to v1 crypto

✅ after uninstalling all 3rd party plugins, both v2 crypto diagnostics pass

✅ diagnostics also detect linked plugins with old sfdx-core

v1 crypto + generic unix keychain

✅ no plugins, diagnostics detect full v2 crypto support and that v1 is being used

v1 crypto + macos keychain

✅ detect v2 crypto supported, can't tell which one is being used.

CLI installed via installer, disabled installed node/nvm (nvm unload)

install a 3rd party plugin so that the diagnostic tries to run npm, also make sure npm is not available globally (which npm)

❌ diagnostic fails with npm: command not found:

we can't rely on npm being installed, plugin-trust/plugins bundle npm then use that to run commands:

plugin-trust:
https://github.com/salesforcecli/plugin-trust/blob/fd3540ff98d4749c8d06a614114351b4e176a478/src/shared/npmCommand.ts#L82

plugin-plugins:
https://github.com/oclif/plugin-plugins/blob/5336f76963892f2e6dc7f4a3d7fa5787dcd02229/src/util.ts#L93

if it's not worth maybe we can disable checks that need to run npm if it's not available.

[cristiand391]

QA update:

✅ can see auth crypto diagnostics when npm is available on PATH
✅ if no npm, test prints:

  * Couldn't determine latest CLI version due to:
/bin/sh: npm: command not found

with exit code 0