Improve NEOS email verification error message

[jsiirola]

Fixes #N/A

Summary/Motivation:

This PR improved the error message generated when the NEOS interface can't identify a suitable email address.

Changes proposed in this PR:

• include attempted email address in the error message from Kestrel

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.

[codecov]

Codecov Report

Merging #1783 (616589a) into master (fe654c2) will increase coverage by 5.61%.
The diff coverage is 75.00%.

@@            Coverage Diff             @@
##           master    #1783      +/-   ##
==========================================
+ Coverage   69.33%   74.95%   +5.61%     
==========================================
  Files         637      638       +1     
  Lines       91698    91779      +81     
==========================================
+ Hits        63582    68796    +5214     
+ Misses      28116    22983    -5133     

Impacted Files	Coverage Δ
pyomo/neos/kestrel.py	81.36% <75.00%> (+12.87%)	⬆️
pyomo/checker/runner.py	88.60% <0.00%> (-8.54%)	⬇️
pyomo/solvers/plugins/converter/model.py	75.00% <0.00%> (-4.78%)	⬇️
pyomo/repn/plugins/baron_writer.py	73.74% <0.00%> (-3.39%)	⬇️
examples/dae/simulator_ode_example.py	50.00% <0.00%> (-3.34%)	⬇️
examples/dae/simulator_ode_multindex_example.py	60.65% <0.00%> (-3.14%)	⬇️
pyomo/core/base/PyomoModel.py	78.70% <0.00%> (-1.26%)	⬇️
...yomo/core/plugins/transform/radix_linearization.py	9.86% <0.00%> (-0.20%)	⬇️
pyomo/solvers/plugins/solvers/glpk_direct.py	7.10% <0.00%> (-0.08%)	⬇️
pyomo/pysp/plugins/interscenario.py	0.00% <0.00%> (ø)
... and 149 more

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