Fix flaky diagnostics redaction integration test (#7414) (#7482)

The test expects to see a particular input from a fleet policy in
diagnostic output, but doesn't wait until the policy is actually
applied.

(cherry picked from commit 8af1feb)

Co-authored-by: Mikołaj Świątek <mail@mikolajswiatek.com>

Author: mergify[bot]

testing/integration/diagnostics_test.go

@@ -257,6 +257,11 @@ func TestRedactFleetSecretPathsDiagnostics(t *testing.T) {
 	require.NoErrorf(t, err, "Error when installing agent, output: %s", out)
 	check.ConnectedToFleet(ctx, t, fixture, 5*time.Minute)
 
+	// wait until the agent acknowledges the policy change
+	require.Eventually(t, func() bool {
+		return checkinWithAcker.Acked(policyChangeAction.ActionID)
+	}, time.Minute, time.Second)
+
 	t.Log("Gather diagnostics.")
 	diagZip, err := fixture.ExecDiagnostics(ctx)
 	require.NoError(t, err, "error when gathering diagnostics")