[Feature]: Warn on createFileSessionStorage dir inside app

[sergiodxa]

What is the new or updated feature that you are suggesting?

When you use createFileSessionStorage show a warning or throw if the dir is inside the app folder.

Why should this feature be included?

Right now you can put the file inside app, and if you do that and commit the session in a loader (e.g. to read a flas message) the commit will update the file and in development it will cause a reload, which will run the loader again and commit the session again causing the file to change again repeating the cycle and causing an infinite loop.

In production is not an issue, but the function should probably warn if you put the dir to be inside app to avoid this issue.