Simplify migration LegacyBridge example

[jzohrab]

Rather than return null and then return the prior request, just send the request, and fall back to the LegacyBridge if needed.

I implemented my LegacyBridge following the example given in the docs (thank you for the starting point!) and then realized that the code flow could be simplified. Cheers and regards! jz

[javiereguiluz]

@dbrumann if you have some time, we'd love to read your opinion about this refactorization. Thanks!

[jzohrab]

Let me know if I can provide anything that would expedite or simplify the review for you. Thanks again for the head start this gave me. First symfony project for me so every little bit helps. Cheers!

[dbrumann]

Overall, I think the changes are good. I am glad the existing docs helped as a starting point.

[dbrumann]

Thanks for the changes. I think this makes it clearer. I have left some more minor suggestions, but nothing critical.

I like this better than the original version, so 👍 from my side.

[jzohrab]

I like this better than the original version, so 👍 from my side.

Thanks for the feedback, everything has been incorporated. Cheers! z

[OskarStark]

Friendly ping @derrabus

[derrabus]

No objection from my side.

[OskarStark]

Great work, thank your for this contribution and congratulations on your first contribution to the Symfony Documentation 👏🎉