Improve FAST's binding volatility detection

[m-akinc]

🧹 Tech Debt

See PR thread.

Filed bug to FAST. This Nimble tech debt issue assumes that we will have to be the ones to fix the FAST issue by doing the following:

• Add ?? to FAST's regex pattern used to determine if a binding needs to be marked volatile.
• Also, fix the createAggregateBinding function so that it properly detects/sets volatility for the created binding. See the version of the function in the main branch.

We should ensure this is fixed in both the archived fast-element branch and the mainline.