Allow estimate to run without redshift

[raphaelshirley]

Closes #49

Allow running of estimate without redshift

Code Quality

• My code follows the code style of this project
• I have written unit tests or justified all instances of #pragma: no cover; in the case of a bugfix, a new test that breaks as a result of the bug has been added
• My code contains relevant comments and necessary documentation for future maintainers; the change is reflected in applicable demos/tutorials (with output cleared!) and added/updated docstrings use the NumPy docstring format
• Any breaking changes, described above, are accompanied by backwards compatibility and deprecation warnings

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 46.03%. Comparing base (822f486) to head (03ba798).

Files	Patch %	Lines
src/rail/estimation/algos/lephare.py	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #50      +/-   ##
==========================================
- Coverage   47.15%   46.03%   -1.13%     
==========================================
  Files           2        2              
  Lines         123      126       +3     
==========================================
  Hits           58       58              
- Misses         65       68       +3     

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[drewoldag]

This seems reasonable enough, given that this is an internal method. This might be a good place to add some more tests down the line.