[Bug] Frontend build script fails cryptically when npm is missing

[hhvrc]

Pre-submission checklist

• [X] I checked that no other Bug Report describing my problem exists.
• [X] I am running the latest stable or prerelease firmware.
• [X] My board is on the list of maintained boards.
• [X] I accept that this issue may be closed if any of the above are found to be untrue.

Board

Not applicable

Firmware version

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Flashing method

Not applicable

Describe what happened as precisely as possible.

get_fa_icon_map() in scripts/build_frontend.py returns an empty array

Describe what you expected to happen instead.

We should have some more verbose failure

In as much detail as possible, describe the exact steps you took to make the problem appear.

Dunno, guess try to compile firmware without npm?

Other remarks

No response