Add input checks on analytic beam interp parameters

[bhazelton]

Description

Add input checking to AnalyticBeam.interp to give clearer error messages.

Motivation and Context

fixes #374

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Reference simulation update or replacement
• [ ] Documentation change (documentation changes only)
• [ ] Version change
• [ ] Build or continuous integration change

Checklist:

For all pull requests:

• [x] I have read the contribution guide.
• [x] My code follows the code style of this project.

Bug fix checklist:

• [x] My fix includes a new test that breaks as a result of the bug (if possible).
• [x] All new and existing tests pass.
• [ ] I have checked that I reproduce the reference simulations or if there are differences they are explained below (if appropriate). If there are changes that are correct, I will update the reference simulation files after this PR is merged.
• [ ] I have checked (e.g., using the benchmarking tools) that this change does not significantly increase typical runtimes. If it does, I have included a justification in the comments on this PR.
• [ ] I have updated the CHANGELOG.

[codecov[bot]]

Codecov Report

Merging #377 (73fd9a5) into main (c7c1456) will increase coverage by 0.00%. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #377   +/-   ##
=======================================
  Coverage   99.14%   99.15%           
=======================================
  Files          13       13           
  Lines        1997     2001    +4     
=======================================
+ Hits         1980     1984    +4     
  Misses         17       17           

Impacted Files	Coverage Δ
pyuvsim/analyticbeam.py	100.00% <100.00%> (ø)

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