Add Ender-3 Pro without clip boundaries for magnetic bed

[kazooless]

In this discussion: #7252

Some were pointing out the Ender-3 Pro comes with a magnetic bed without clips making the entire surface of the bed printable. The disallowed areas in the standard Ender-3 are not easily removed. @Ghostkeeper seemed to indicate a new "Pro" profile is an acceptable solution. So, here it is.

P.S. I'm still very new to GitHub. I made this change in the 4.6 branch instead of master this time. Is this correct? (preferred by you?)

[Ghostkeeper]

P.S. I'm still very new to GitHub. I made this change in the 4.6 branch instead of master this time. Is this correct? (preferred by you?)

For Github this is fine. You can aim a PR to be merged into any branch. However for the Cura team's workflow it's incorrect. Before we start the public beta we always have a feature freeze. That means that only bugfixes are allowed in 4.6 at the moment. That's necessary to get the release stable. I hope you understand.

I'll change the base of this PR to master. That way it can get merged into 4.7 instead (which we will branch off in about 2 months).

[Ghostkeeper]

Seems to work fine. No more clip collision areas. Thanks!