Optimize `PrimitiveBuilder::append_trusted_len_iter`

[alamb]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

• part of [EPIC] Faster performance for parquet predicate evaluation for non selective filters #7456

@Dandandan noted on https://github.com/apache/arrow-rs/pull/7513/files#r2119136807:

Looking at the code - this doesn't actually really use the TrustedLen optimization.
I think it could use the same optimization as MutableBuffer::from_trusted_len

Describe the solution you'd like
Let's optimize that function!

Describe alternatives you've considered

Additional context

[alamb]

With @Dandandan I think we are going to go a different direction and use Vec instead of optimizing PrimitiveBuilder