Refactor LRE functions for large circuits

[purva-thakre]

Code coverage for inference functions

• managed to trigger the following warning when input_degree=5 and fold_multiplier=3 for this unit test.

mitiq/mitiq/lre/inference/multivariate_richardson.py

Lines 167 to 170 in 1a3705c

	warnings.warn( # pragma: no cover
	"To account for overflow error, required determinant of "
	+ "large sample matrix is calculated through "
	+ "`np.linalg.slogdet`."

[natestemen]

@purva-thakre can you add more details about what needs to be done here? Is the issue about adding a test that triggers that warning or refactoring code to make it not needed?