[EventHubs] Enable the FxCop Analysizers

[ellismg]

As a follow up to #11414, I was trying to understand why did not see
errors from the "FxCop Analyiszers", which would have pointed out that
issue to us.

The reason was simple - we had disabled the analysis for these projects.

I've re-enabled them, either fixing up issues or adding suppressions.
We ended up catching some reasonable errors (a few cases where we called
the ArgumentException constructor but messed up the order of the message
and the parameter name) as well as a case where we were passing two
parameters to an internal method but then disregarding them. In
practice, the code we had was still "correct", because it happened to
only be called from a single place today and the only caller was passing
the same values that the implementation was actually using.

Overall, I think taking this would be worthwhile. It brings this library
back in line with the the others. I could imagine some library wide
supressions of rules here, specifically the one about not calling
virtual methods from constructors, since in practice we are unlikely to
hit the problems the rule intends to guard for, but for now I've just
made the diff look "as bad as possible" by doing supressions around the
offending lines with justifications.

[jsquire]

LGTM. Thanks for kicking the tires on this. The analyzer spam seems far less plentiful than the last time we thought to try and enable it. Not a fan of the #pragma blocks that we need, but I'd agree its the lesser of evils.