refactor: replace context.Background() with t.Context()/b.Context() in tests (#7352)

Based on the Go version we currently use, the dependency already
supports 1.24+, which allows using `t.Context()` and `b.Context()` in
unit tests and benchmarks respectively.

- Enable `context-background` and `context-todo` in
[`usetesting`](https://golangci-lint.run/docs/linters/configuration/#usetesting)
- Adjust the code to support linter detection

---------

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
Co-authored-by: Tyler Yahn <codingalias@gmail.com>
Co-authored-by: Damien Mathieu <42@dmathieu.com>

trace/noop_test.go

@@ -4,7 +4,6 @@
 package trace
 
 import (
-	"context"
 	"testing"
 )
 
@@ -24,7 +23,7 @@ func TestNoopTracerProviderTracer(t *testing.T) {
 }
 
 func TestNoopTracerStart(t *testing.T) {
-	ctx := context.Background()
+	ctx := t.Context()
 	tracer := NewNoopTracerProvider().Tracer("test instrumentation")
 
 	var span Span
@@ -48,7 +47,7 @@ func TestNoopTracerStart(t *testing.T) {
 
 func TestNoopSpan(t *testing.T) {
 	tracer := NewNoopTracerProvider().Tracer("test instrumentation")
-	_, s := tracer.Start(context.Background(), "test span")
+	_, s := tracer.Start(t.Context(), "test span")
 	span := s.(noopSpan)
 
 	if got, want := span.SpanContext(), (SpanContext{}); !assertSpanContextEqual(got, want) {
@@ -71,7 +70,7 @@ func TestNonRecordingSpanTracerStart(t *testing.T) {
 	}
 	sc := NewSpanContext(SpanContextConfig{TraceID: tid, SpanID: sid})
 
-	ctx := ContextWithSpanContext(context.Background(), sc)
+	ctx := ContextWithSpanContext(t.Context(), sc)
 	_, span := NewNoopTracerProvider().Tracer("test instrumentation").Start(ctx, "span1")
 
 	if got, want := span.SpanContext(), sc; !assertSpanContextEqual(got, want) {