Fixes panic on Go instrumentation (1.9 branch patch)

[mariomac]

On ELF parse error, we return the list of missing fields, assuming that we would stop the instrumentation. There is an edge case error on which the missing fields set is empty so Beyla keeps with the instrumentation, but the returned list of fields is nil.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 72.58%. Comparing base (6d9088b) to head (e54cddc).

Files with missing lines	Patch %	Lines
pkg/internal/goexec/structmembers.go	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (6d9088b) and HEAD (e54cddc). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (6d9088b)	HEAD (e54cddc)
unittests	1	0

Additional details and impacted files

@@               Coverage Diff               @@
##           release-1.9    #1474      +/-   ##
===============================================
- Coverage        81.15%   72.58%   -8.57%     
===============================================
  Files              146      145       -1     
  Lines            14828    14819       -9     
===============================================
- Hits             12033    10757    -1276     
- Misses            2206     3349    +1143     
- Partials           589      713     +124     

Flag	Coverage Δ
integration-test	58.29% <0.00%> (-0.04%)	⬇️
k8s-integration-test	60.15% <0.00%> (+0.04%)	⬆️
oats-test	33.88% <0.00%> (ø)
unittests	?

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[rafaelroquetto]

Carried over to #1477