[receiver/awsxrayreceiver] Update to latest semconv version

[anarwal]

Description

1. metadata.yaml — Added feature gates (DontEmitV0HTTP, EmitV1HTTP, DontEmitV0DB, EmitV1DB)
2. internal/translator/http.go — Removed v1.18.0/v1.20.0/v1.25.0 imports, added v1.40.0 + metadata. All HTTP attribute emissions gated with dual-emit pattern.
3. internal/translator/sql.go — Removed v1.25.0/v1.28.0 imports, added v1.40.0 + metadata. All DB attribute emissions gated. db.connection_string and db.user have no new equivalent (removal only).
4. .chloggen/awsxrayreceiver-semconv-feature-gates.yaml — Changelog entry

All gates default to disabled → old behavior preserved. Users opt-in to new attributes via EmitV1 gates, opt-out of old via DontEmitV0 gates.

Link to tracking issue

Fixes receiver/awsxrayreceiver from #22095

Testing

Ran the following successfully locally

• go build ./...
• go test ./...
• go mod tidy 2>&1

from receiver/awsxrayreceiver

Authorship

• I, a human, wrote this pull request description myself.