fix(otel): recognize db spans that use the stable OpenTelemetry database attributes

[michielvandermeer]

Description

SentrySpanProcessor treats a span as a database span only when it has db.system, and takes the query from db.statement. The stable OpenTelemetry database conventions (v1.33.0) renamed these to db.system.name (v1.30.0) and db.query.text (v1.26.0). Instrumentation that follows them, such as Npgsql 10, sends only the new names. The processor then skips its database branch, so every Npgsql query reaches Sentry with op postgresql and description postgresql. The SQL appears nowhere in the trace view, and the spans never show in Queries insights.

ParseOtelSpanDescription now reads the new names first and falls back to the old ones, through two helpers in OpenTelemetryExtensions (HasDbSystemAttribute, DbQueryTextAttribute). This is the same pattern HttpMethodAttribute and UrlFullAttribute already use. Relay already understands db.system.name in span data, and the processor already copies every attribute into the span's data, so recognizing the span here is the only missing piece.

Notes for review:

• Spans that carry only db.system and db.statement take the same path as before. The new tests cover both the old and the new names. With the SentrySpanProcessor.cs change reverted, only the two new-name cases fail.
• Spans that send only the new names change op from the activity's operation name (for Npgsql, postgresql) to db, and their description to the query. A span that sends both old and new names now takes its description from db.query.text.
• I ran Sentry.OpenTelemetry.Tests on net10.0 (49 passed). The net8.0 and net9.0 targets build, but I don't have those runtimes installed, so CI covers them.

Issues

No issue tracks this. #5435 touches the same database branch of SentrySpanProcessor.

Reminders

• Add tests that verify your change.
• PR title should use conventional commit style (feat:, fix:, chore:, meta:) — it becomes the changelog entry. Do not edit CHANGELOG.md manually; mark changes that aren't user-facing with skip-changelog
• For external contributors: CONTRIBUTING.md, Sentry SDK development docs, Discord community

🤖 Generated with Claude Code

[jamescrosswell]

Hi @michielvandermeer - thanks for the PR. However we've marked the Sentry.OpenTelemetry as obsolete:

• feat(otel): mark span processor based OpenTelemetry setup methods as obsolete #5586

We'd recommend you migrate to Sentry.OpenTelemetry.Exporter instead as that's where all future OTEL development will happen.