Raise an error if qml.probs is called without wires or obs

[antalszava]

Closes #2401.

[github-actions]

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[antalszava]

[sc-17088]

[rmoyard]

Thank you @antalszava it looks good to me! 💯

[codecov]

Codecov Report

Merging #2438 (ce3e3f1) into master (afc9adc) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2438   +/-   ##
=======================================
  Coverage   99.45%   99.45%           
=======================================
  Files         242      242           
  Lines       18971    18973    +2     
=======================================
+ Hits        18868    18870    +2     
  Misses        103      103           

Impacted Files	Coverage Δ
pennylane/measurements.py	99.43% <100.00%> (+<0.01%)	⬆️

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