BUG: Keep array arguments working in the validated stats functions - #10434

The checks added in GH-10379, GH-10386, GH-10388, GH-10392, GH-10393,
GH-10399, GH-10405, GH-10406, GH-10411, GH-10420, GH-10421, GH-10423,
GH-10425, GH-10426 and GH-10431 compare the arguments with scalars,
for example if not 0 < alpha < 1, if low > upp or if dispersion < 0.
These raise "The truth value of an array with more than one element is
ambiguous" for arrays and Series. The functions broadcast over these
arguments and return the same values as the calls for the elements in
0.15.0, for example a confidence interval for several alpha, the power
for several equivalence margins or a table of sample sizes.

Test with np.all and the comparison ufuncs instead, which work for
scalars, lists, arrays and Series, and which also reject NaN. The
error messages are unchanged. A new test checks for 50 arguments that an
array of two valid values gives the same result as the two calls with the
scalars, and that one invalid element (including NaN) is rejected.

Follow-up to GH-10379, GH-10386, GH-10388, GH-10392, GH-10393, GH-10399,
GH-10405, GH-10406, GH-10411, GH-10420, GH-10421, GH-10423, GH-10425,
GH-10426, GH-10431

• tests added / passed.
• code/documentation is well formatted.
• properly formatted commit message. See
  NumPy's guide.

AI Disclosure

Contributions must comply with the statsmodels AI Policy.

Tick exactly one of the following. If AI tools were used, replace the <...>
placeholders in the second option with the tool name(s) and how the tool's output was
used.

• No AI tools were used to develop this pull request.
• AI tools were used.
  Tool(s): Claude Sonnet
  Used for: Automated site detection and doc string correction
  I have personally read, understood, and can explain every line of this diff, and
  have verified the statistical/numerical correctness of the change.