Fixes panic on Go instrumentation

[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 73.03%. Comparing base (1192264) to head (483a2c9).

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 (1192264) and HEAD (483a2c9). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (1192264)	HEAD (483a2c9)
unittests	1	0

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1475      +/-   ##
==========================================
- Coverage   81.45%   73.03%   -8.43%     
==========================================
  Files         149      148       -1     
  Lines       15253    15244       -9     
==========================================
- Hits        12425    11133    -1292     
- Misses       2228     3386    +1158     
- Partials      600      725     +125     

Flag	Coverage Δ
integration-test	59.77% <0.00%> (-0.01%)	⬇️
k8s-integration-test	60.77% <0.00%> (+0.90%)	⬆️
oats-test	34.02% <0.00%> (ø)
unittests	?

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[rafaelroquetto]

Carried over to #1476