Fix Numpy1.25 deprecation

[ericpre]

See failure in https://github.com/hyperspy/hyperspy-extensions-list/actions/runs/5434206100/jobs/9882458789

_____________ ERROR collecting tests/signals/test_find_peaks2D.py ______________
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/runner.py:341: in from_call
    result: Optional[TResult] = func()
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/runner.py:372: in <lambda>
    call = CallInfo.from_call(lambda: list(collector.collect()), "collect")
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/python.py:531: in collect
    self._inject_setup_module_fixture()
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/python.py:545: in _inject_setup_module_fixture
    self.obj, ("setUpModule", "setup_module")
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/python.py:310: in obj
    self._obj = obj = self._getobj()
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/python.py:528: in _getobj
    return self._importtestmodule()
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/python.py:617: in _importtestmodule
    mod = import_path(self.path, mode=importmode, root=self.config.rootpath)
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/pathlib.py:565: in import_path
    importlib.import_module(module_name)
/usr/share/miniconda3/envs/test/lib/python3.11/importlib/__init__.py:126: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
<frozen importlib._bootstrap>:1204: in _gcd_import
    ???
<frozen importlib._bootstrap>:1176: in _find_and_load
    ???
<frozen importlib._bootstrap>:1147: in _find_and_load_unlocked
    ???
<frozen importlib._bootstrap>:690: in _load_unlocked
    ???
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/_pytest/assertion/rewrite.py:178: in exec_module
    exec(co, module.__dict__)
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/hyperspy/tests/signals/test_find_peaks2D.py:[97](https://github.com/hyperspy/hyperspy-extensions-list/actions/runs/5434206100/jobs/9882458789#step:18:98): in <module>
    DATASETS = _generate_dataset()
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/hyperspy/tests/signals/test_find_peaks2D.py:73: in _generate_dataset
    sparse_nav2d_shifted.align2D(shifts=shifts, fill_value=0)
/usr/share/miniconda3/envs/test/lib/python3.11/site-packages/hyperspy/_signals/signal2d.py:749: in align2D
    int(np.floor(signal_shifts.isig[0].min().data)) if signal_shifts.isig[0].min().data < 0 else None,
E   DeprecationWarning: Conversion of an array with ndim > 0 to a scalar is deprecated, and will error in future. Ensure you extract a single element from your array before performing this operation. (Deprecated NumPy 1.25.)

Progress of the PR

• Fix Numpy1.25 deprecation: implicite array to scalar conversion in align2D,
• [n/a] update docstring (if appropriate),
• [n/a] update user guide (if appropriate),
• add an changelog entry in the upcoming_changes folder (see upcoming_changes/README.rst),
• Check formatting changelog entry in the readthedocs doc build of this PR (link in github checks)
• [n/a] add tests,
• ready for review.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.05 ⚠️

Comparison is base (3e7a7e0) 81.27% compared to head (067c661) 81.23%.

Additional details and impacted files

@@                  Coverage Diff                   @@
##           RELEASE_next_major    #3189      +/-   ##
======================================================
- Coverage               81.27%   81.23%   -0.05%     
======================================================
  Files                     176      176              
  Lines                   24401    24409       +8     
  Branches                 5683     5683              
======================================================
- Hits                    19833    19829       -4     
- Misses                   3261     3274      +13     
+ Partials                 1307     1306       -1     

Impacted Files	Coverage Δ
hyperspy/_signals/signal2d.py	81.84% <100.00%> (+0.44%)	⬆️

... and 2 files with indirect coverage changes

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