BEAUTi: missing Tree prior parameters when switching between templates

[jugne]

When switching between tree prior subtemplates that use the same class, tree parameters are not updated correctly.
This is because members are added to beastfx.app.inputeditor.BeautiConfig.suppressBEASTObjects set on loading the subtemplates and then never removed if subtemplate changes.

To reproduce with version 2.7.7 and BDSky package:

• first select Birth Death Skyline Multi Rho template and expand Tree panel.
• then select Birth Death Skyline Contemporary template, notice that Rho Sampling Times in Tree panel disappear (this is correct behaviour)
• go back to the Birth Death Skyline Multi Rho template. The Rho Sampling Times parameter in Tree panel does not appear again, which it should.