Use the Paradox 2 mlr3mbo bridge

[mb706]

Require mlr3mbo >= 1.2.1.9000, the compatible development bridge and
predecessor of the intended >= 1.2.2 release, so released 1.2.0/1.2.1 cannot
select their unsupported private-Domain path on Paradox 2. Keep the
design-grid comparison meaningful on both Paradox generations: Paradox 2's
native dependency planner and celecx reject the same cycle at different
boundaries, so assert each package-owned cycle diagnostic instead of
requiring the two implementation messages to be identical. Ordinary value
diagnostics remain on their original precise assertions.

Stop assigning NULL to obsolete active bindings in the test surrogate and
assert the public data.table prediction result instead.

• Accept Paradox 2 validation diagnostics
• Require the transform-free mlr3mbo bridge
• Restore precise Paradox validation assertions
• Require the released Paradox 2 mlr3mbo bridge
• Align tests with current mlr3mbo surrogate contract