Relax CI constraint on numpy<1.25

The major problem in NumPy 1.25 transpired to be that particular
versions of Apple clang (including the one used in Numpy's wheel-build
CD pipelines) produced non-deterministic code from new SIMD routines for
complex multiplication.  This in turn destabilised our `Isometry`
decompositions, which caused major correctness problems.  As of Numpy
1.26.1 (released 2023-10-14), that SIMD code now decays to the scalar
form if the compiler was known to be buggy, which restores the previous
behaviour.

constraints.txt

@@ -2,11 +2,6 @@
 # 4.0+. The pin can be removed after nbformat is updated.
 jsonschema==3.2.0
 
-# Numpy 1.25 deprecated some behaviours that we used, and caused the isometry
-# tests to flake. See https://github.com/Qiskit/qiskit-terra/issues/10305,
-# remove pin when resolving that.
-numpy<1.25
-
 # Scipy 1.11 seems to have caused an instability in the Weyl coordinates
 # eigensystem code for one of the test cases.  See
 # https://github.com/Qiskit/qiskit-terra/issues/10345 for current details.