ddtrace/tracer: add integration tag to spans_started/finished #3737

Job	Run time
Prepare Go modules cache	10s
Smoke Tests	0s
macos-13 go1.23	4m 31s
macos-latest (AppSec disabled)	1m 57s
linux/amd64 golang:1.23-bookworm	1m 19s
macos-13 go1.22	8m 48s
windows-latest (AppSec disabled)	4m 15s
linux/arm64 golang:1.23-bookworm	3m 17s
macos-15 go1.23	3m 58s
ubuntu-latest-16-cores (AppSec disabled)	1m 16s
linux/amd64 golang:1.23-bullseye	1m 22s
macos-15 go1.22	4m 17s
linux/arm64 golang:1.23-bullseye	3m 5s
linux/amd64 golang:1.23-alpine	1m 15s
linux/arm64 golang:1.23-alpine	2m 58s
linux/amd64 golang:1.22-bookworm	1m 29s
linux/arm64 golang:1.22-bookworm	3m 14s
linux/amd64 golang:1.22-bullseye	1m 19s
linux/arm64 golang:1.22-bullseye	3m 3s
linux/amd64 golang:1.22-alpine	1m 24s
linux/arm64 golang:1.22-alpine	2m 52s
	55m 49s

Provide feedback