Refactor and add tests for component_range

[moCello]

Describe what you want implemented
Add in-circuit tests for the composer methods

• component_range

Describe "Why" this is needed
Increase test coverage

Describe alternatives you've considered
N/A

Additional context
Continuation of #731

[moCello]

Turns out that no constraint is added when num_bits = 0. This means that a circuit that constraints a witness to be encoded in 0 bits will always pass. This is an edge case but should be fixed nonetheless. See issue #746