Fix sample measuring hamiltonians with a shot vector

[albi3ro]

[sc-40254]

Finite shot measurements of Hamiltonians and sums was not working with shot vectors. This PR adds shot vector coverage.

shots = Shots((100, 100))
state = create_initial_state((0,))
measure_with_samples(qml.expval(qml.PauliX(0)+qml.PauliY(0)), state,shots=shots)

(tensor(-0.06, requires_grad=True), tensor(-0.16, requires_grad=True))

[github-actions]

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[codecov]

Codecov Report

Merging #4254 (56fde34) into master (ccf24c6) will increase coverage by 99.78%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           master    #4254       +/-   ##
===========================================
+ Coverage        0   99.78%   +99.78%     
===========================================
  Files           0      352      +352     
  Lines           0    31733    +31733     
===========================================
+ Hits            0    31665    +31665     
- Misses          0       68       +68     

Impacted Files	Coverage Δ
pennylane/devices/qubit/sampling.py	100.00% <100.00%> (ø)

... and 351 files with indirect coverage changes

[eddddddy]

LGTM 💯