We already have a way to reset the entire active blueprint to the default one set in code.
What we need is to do the same for individual properties.

For instance, when resetting the 2D view bounds, we should reset to whatever was set in code.

Implementation

The active blueprint is a clone of the default blueprint, with new values appended to it.
This means we can implement this is one out of a few different ways:

A) Read the value from the default blueprint and append it to the active one
B) Remove the value in the active blueprint, and then copy the full history of the value from the default blueprint

B) requires something like #1329 to be implemented.