Fix asoctl aborting import when an error occurs

[theunrepentantgeek]

What this PR does / why we need it:

It's possible to encounter an error querying ARM for child resources that don't exist.
This currently causes asoctl to abort the import run but shouldn't.

Fixes #3200

Special notes for your reviewer:

Amongst other causes, errors mayoccur if the subscription hasn't onboarded for a particular resource provider, or if the subscription doesn't have access to a particular new feature.

How does this PR make you feel:

[codecov-commenter]

Codecov Report

Merging #3212 (cb08cc4) into main (239eea7) will increase coverage by 0.02%.
Report is 1 commits behind head on main.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #3212      +/-   ##
==========================================
+ Coverage   54.39%   54.41%   +0.02%     
==========================================
  Files        1424     1424              
  Lines      601351   601360       +9     
==========================================
+ Hits       327097   327230     +133     
+ Misses     220754   220622     -132     
- Partials    53500    53508       +8     

Files Changed	Coverage Δ
...octl/internal/importing/importable_arm_resource.go	2.60% <0.00%> (-0.04%)	⬇️
...d/asoctl/internal/importing/importable_resource.go	37.14% <ø> (ø)
...cmd/asoctl/internal/importing/resource_importer.go	0.00% <0.00%> (ø)

... and 28 files with indirect coverage changes

[matthchr]

Lacking a test related to this problem. I see that (like the core logic of the controller) it's somewhat difficult to unit test this code as it stands today. In the controller though we do have the recording tests to fall back on.

Wondering here if we should define an interface that allows us to mock certain errors from Azure for aid in testing these cases? We actually already have one in extensions.ImporterFunc... possibly we could leverage that with some test helpers to make it ergonomic to mock certain error responses from Azure and ensure we handle them?

Approved because I don't necessarily think that should come in this PR, but maybe we should think about it and file an item for it?

[matthchr]

minor: Wrong ordering, should be below with the non-stdlib imports.

[matthchr]

minor: fix docs