fix: leveragingbagging parameter configuration

[waddason]

Issue
While tuning hyper-parameters with a LeverageBagging classifier, I got an error when specifying the number_of_jobs but without using the minbatch_size parameter.
On instantiation, the classifier checks if minibatch_size <= 1 but minibatch is still None. This raises an exception.

Proposed solution
Switch the test order for minibatch_size, starting with the is None test.
The existing comments and documentation are still relevant.

[hmgomes]

Hi @waddason , it took a while to get to this PR, but here we are. Thanks for raising the problem

Hi @cassales could you please assist with this one?

[cassales]

Hi @waddason and @hmgomes,

I have taken a look, and indeed, I messed up. Thanks for fixing it, @waddason!
The only issue is that the commit message does not comply with the project's standards.
Please amend it to have all lowercase and less than 80 characters.

[waddason]

Hi @cassales , I have amended the commit message. Do you need any other action from my part ?