Adding qml.MultiplexerStatePreparation

[KetpuntoG]

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---

Context:

A new template MultiplexerStatePreparation has been added. This template allows prepare arbitrary states
using SelectPauliRot operations.

[sc-100288]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.43%. Comparing base (768083a) to head (b5e6576).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8581   +/-   ##
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  Coverage   99.43%   99.43%           
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  Files         588      589    +1     
  Lines       62727    62783   +56     
=======================================
+ Hits        62373    62429   +56     
  Misses        354      354           

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[obliviateandsurrender]

Thanks @KetpuntoG! Good work, leaving the first set of comments.

[obliviateandsurrender]

Should we always do the norm computation?

[KetpuntoG]

What do you mean here? Maybe adding an attribute "check"?
(I based this in QROMStatePreparation)

[obliviateandsurrender]

Won't this also be queuing under the queuing context? 🤔

[KetpuntoG]

I checked with Astral and he linked to this example:

pennylane/pennylane/ops/qubit/arithmetic_ops.py

Line 555 in 3fbee20

def compute_decomposition(

[DSGuala]

[SC-104270]