Remove TLS check from environment file whilst it is not reliable

In MDL-55404 we added checks for curl versions to detect situations where TLS 1.2 can't be used, which affects integrations with external services (as well as our own updates service).

Unfortunately it has come to light that the version sniffing is just not reliable at all, operating system vendors backport security patches to older versions - so in many cases we reporting a problem which is not a problem. False positives and the solution to self-compile or something like php will be causing more harm than good.

To solve this properly, we need to stop sniffing versions, and instead do a real test of TLS support - MDL-57262 is open about this.

But in the meantime, to prevent these false positves causing problems for people upgrading, we will remove the check from 3.2 environment requirements.