Remove beyla metrics and traces by default

[grcevski]

When we switched to the OpenTelemetry collector SDK for generating traces we ended up accidentally enabling Beyla internal metrics and traces. This PR reverts that setting. If the internal metrics Prometheus port is enabled, the trace exporter metrics get enabled now.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 82.60870% with 4 lines in your changes missing coverage. Please review.

Project coverage is 66.67%. Comparing base (cd4f89d) to head (dd591c9).

Files	Patch %	Lines
pkg/internal/export/otel/traces.go	82.60%	2 Missing and 2 partials ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #910       +/-   ##
===========================================
- Coverage   78.93%   66.67%   -12.27%     
===========================================
  Files         131      130        -1     
  Lines        9742     9746        +4     
===========================================
- Hits         7690     6498     -1192     
- Misses       1553     2671     +1118     
- Partials      499      577       +78     

Flag	Coverage Δ
integration-test	55.20% <82.60%> (+0.14%)	⬆️
k8s-integration-test	58.91% <82.60%> (+0.03%)	⬆️
oats-test	?
unittests	?

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