Update Go version to 1.23

[mariomac]

Just checking that no breaking changes are introduced in this version. The merge of this PR can be deferred after all the other PRs are merged, to avoid conflicts.

This PR also fixes some slog.Error invocations that were wrong. In Go 1.22 it caused some wrong-format output but in Go 1.23 they are treated as compile errors.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 6.25000% with 15 lines in your changes missing coverage. Please review.

Project coverage is 82.00%. Comparing base (74ba237) to head (3025daf).
Report is 4 commits behind head on main.

Files	Patch %	Lines
cmd/beyla/main.go	0.00%	4 Missing ⚠️
pkg/internal/ebpf/common/ringbuf.go	0.00%	4 Missing ⚠️
pkg/export/otel/traces.go	0.00%	2 Missing ⚠️
pkg/internal/discover/attacher_linux.go	0.00%	2 Missing ⚠️
pkg/export/debug/debug.go	0.00%	1 Missing ⚠️
pkg/export/otel/metrics_proc.go	0.00%	1 Missing ⚠️
pkg/internal/connector/prommgr.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1105      +/-   ##
==========================================
+ Coverage   81.91%   82.00%   +0.09%     
==========================================
  Files         140      140              
  Lines       11450    11514      +64     
==========================================
+ Hits         9379     9442      +63     
- Misses       1548     1550       +2     
+ Partials      523      522       -1     

Flag	Coverage Δ
integration-test	57.35% <6.25%> (+0.57%)	⬆️
k8s-integration-test	59.13% <6.25%> (-0.05%)	⬇️
oats-test	37.07% <0.00%> (+0.03%)	⬆️
unittests	52.31% <6.25%> (+0.11%)	⬆️

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