Add lowering for the lapack_dsyevd custom call

[maliasadi]

This lowering will enable the QJIT compilation of qml.BlockEncode and qml.qsvt with variable matrices.

For example, the compilation of the following circuits are now possible

@qml.qjit
@qml.qnode(dev)
def circuit1(A):
    qml.BlockEncode(A, wires=range(2))
    return qml.state()


>>> circuit1(np.array([[0.1, 0.2], [0.3, 0.4]]))

A = np.array([[0.1, 0.2], [0.3, 0.4]])
angles = np.array([0.1, 0.2, 0.3])

@qml.qjit
@qml.qnode(dev)
def circuit2(A):
    qml.qsvt(A, angles, wires=[0, 1])
    return qml.expval(qml.PauliZ(wires=0))

circuit2(A)

[sc-54971]
[sc-55370]

[rmoyard]

Thanks for adding this function, it looks good 👍 Could add an integration test that would call this function and check for correctness?

[rmoyard]

Nice 💯