[Security Solution] Use a stable reference for tour context value (#1…

…60487)

## Summary

The TourContext value was a const object declared in the render of a
component, which meant it was referentially different on every render,
this context provider is so high up in the component tree, this is a
problem and causing some re-renders. Many ways to fix this, but I opted
for something that kept the code as close to the existing code as I
could. A library like why-did-you-render will catch this, also eslint
will if you just try to log the value of context in a useEffect like
below:
<img width="1182" alt="image"
src="https://github.com/elastic/kibana/assets/56408403/64a5c8d3-24f9-4918-a9ba-fc36bbc0b671">
Nothing should change from a functionality/user perspective.

x-pack/plugins/security_solution/public/common/components/guided_onboarding_tour/tour.tsx

@@ -100,13 +100,15 @@ export const RealTourContextProvider = ({ children }: { children: ReactChild })
     setCompleteStep(tourId);
   }, []);
 
-  const context = {
-    activeStep,
-    endTourStep,
-    incrementStep,
-    isTourShown,
-    setStep,
-  };
+  const context = useMemo(() => {
+    return {
+      activeStep,
+      endTourStep,
+      incrementStep,
+      isTourShown,
+      setStep,
+    };
+  }, [activeStep, endTourStep, incrementStep, isTourShown, setStep]);
 
   return <TourContext.Provider value={context}>{children}</TourContext.Provider>;
 };