Potentially rename members of RoundingContext

[garrison]

What is the expected enhancement?

We've talked about renaming the following members of RoundingContext:

prototype-qrao/qrao/rounding_common.py

Lines 65 to 66 in 38527fd

	self.trace_values = trace_values # TODO: rename me
	self.circuit = circuit # TODO: rename me

• trace_values isn't really a standard term (they are really Pauli expectation values)
• the circuit is really a state preparation circuit

[garrison]

I've thought about renaming trace_values to expvals, but it looks like either values or expectation_values would be preferred: Qiskit/qiskit#8100 (comment)