Add troubleshooting notes

[albertteoh]

Which problem is this PR solving?

Document the troubleshooting steps taken while investigating this support question.

One of the problems faced by users was caused by OpenTelemetry Collector Contrib v0.85.0 introducing a breaking change to enable normalized metric names by default:

prometheusexporters: Append prometheus type and unit suffixes by default in prometheus exporters. (open-telemetry/opentelemetry-collector-contrib#26488)
Suffixes can be disabled by setting add_metric_suffixes to false on the exporter.

Relates to: jaegertracing/jaeger#4957

Description of the changes

• Adds the following troubleshooting guides:
  • Inspecting the Prometheus queries that Jaeger makes to fetch data for the Monitor tab.
  • Inspecting OpenTelemetry config to troubleshoot a possible cause for missing error metrics.
• Updates only made from when SPM defaulted to supporting the spanmetrics connector, which was v1.49.0.

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
  - [ ] I have added unit tests for the new functionality
  - [ ] I have run lint and test steps successfully

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