fix(http): change proxy url generation

[jcesarmobile]

On iOS >= 17.2, the proxyUrl.protocol = bridgeUrl.protocol; is not changing the protocol of the proxy url.
Change the proxyUrl generation to return the bridgeUrl, which already has the capacitor protocol and add the other relevant proxyUrl parameters and modified pathname.

closes #7352

[markemer]

Seems to fix the project linked in the ticket, and doesn't break the test app - not sure how else to put it though it's paces, but looks good.