cli: `pio run --list-targets` should show `envdump`, `exec`, `test` [and others?]

Configuration

Operating system: MacOS 12.6.1

PlatformIO Version (platformio --version): 6.1.5

Description of problem

When I type pio run --list-targets I don't see the test target. I guess it should be listed, as it actually exists [?].

Actual Results

✗ pio run --list-targets
Environment    Group     Name         Title                        Description
-------------  --------  -----------  ---------------------------  ----------------------
nodemcuv2      Platform  buildfs      Build Filesystem Image
nodemcuv2      Platform  erase        Erase Flash
nodemcuv2      Platform  size         Program Size                 Calculate program size
nodemcuv2      Platform  upload       Upload
nodemcuv2      Platform  uploadfs     Upload Filesystem Image
nodemcuv2      Platform  uploadfsota  Upload Filesystem Image OTA

Expected Results

Same as above, but also test target listed.

Additional info

I don't know how I know about the test target. Maybe I just experimented, maybe I read about it somewhere in the docs. Anyway, pio run --target test does work, so it is a target, so my intuition is that it should be listed.

Start at the pio run --list-targets CLI entry point and reproduce the output shown in the issue, then compare it with the targets accepted by pio run --target, including test. Done when the listing includes the expected runnable targets and the relevant CLI tests pass.