fix: workaround for otel agent dependency causes orchestrion failure

Moved the blank import of `go.opentelemetry.io/collector/pdata/pprofile``
which was introduced to avoid `go mod tidy` from failing to resolve a
coherent dependency closure into a new file guarded by a build tag so
that it is not present in builds uder normal circumstances.

This removes a dependency cycle caused by the `pprofile` package having
a transitive dependency on `net/http`, while the
`gopkg.in/DataDog/dd-trace-go.v1/internal` package is imported some code
that is injected by orchestrion into `net/http` itself (resulting in a
cycle, breaking builds).

# Conflicts:
#	internal/version/version.go

internal/agent-otel-workaround.go

@@ -0,0 +1,18 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2022 Datadog, Inc.
+
+//go:build otel_workaround
+
+package internal
+
+import (
+	// OTel did a breaking change to the module go.opentelemetry.io/collector/pdata which is imported by the agent
+	// and go.opentelemetry.io/collector/pdata/pprofile depends on it and is breaking because of it
+	// For some reason the dependency closure won't let use upgrade this module past the point where it does not break anymore
+	// So we are forced to add a blank import of this module to give us back the control over its version
+	//
+	// TODO: remove this once github.com/datadog-agent/pkg/trace has upgraded both modules past the breaking change
+	_ "go.opentelemetry.io/collector/pdata/pprofile"
+)