#1554 fix indexing for FEM entries

[rtimms]

Description

Fixes the order of the indexing for the entries of variables solved using FEM

Fixes #1554

Type of change

Please add a line in the relevant section of CHANGELOG.md to document the change (include PR #) - note reverse order of PR #s. If necessary, also add to the list of breaking changes.

• New feature (non-breaking change which adds functionality)
• Optimization (back-end change that speeds up the code)
• Bug fix (non-breaking change which fixes an issue)

Key checklist:

• No style issues: $ flake8
• All tests pass: $ python run-tests.py --unit
• The documentation builds: $ cd docs and then $ make clean; make html

You can run all three at once, using $ python run-tests.py --quick.

Further checks:

• Code is commented, particularly in hard-to-understand areas
• Tests added that prove fix is effective or that feature works

[codecov]

Codecov Report

Merging #1556 (7d611b5) into develop (002ad15) will increase coverage by 0.50%.
The diff coverage is n/a.

❗ Current head 7d611b5 differs from pull request most recent head 7b4905d. Consider uploading reports for the commit 7b4905d to get more accurate results

@@             Coverage Diff             @@
##           develop    #1556      +/-   ##
===========================================
+ Coverage    97.77%   98.28%   +0.50%     
===========================================
  Files          242      310      +68     
  Lines        12639    17398    +4759     
===========================================
+ Hits         12358    17099    +4741     
- Misses         281      299      +18     

Impacted Files	Coverage Δ
pybamm/__init__.py	94.95% <ø> (ø)
pybamm/batch_study.py	100.00% <ø> (ø)
pybamm/citations.py	100.00% <ø> (ø)
pybamm/discretisations/discretisation.py	99.78% <ø> (+<0.01%)	⬆️
pybamm/experiments/experiment.py	100.00% <ø> (+1.81%)	⬆️
pybamm/expression_tree/array.py	100.00% <ø> (ø)
pybamm/expression_tree/binary_operators.py	99.67% <ø> (+4.71%)	⬆️
pybamm/expression_tree/broadcasts.py	100.00% <ø> (ø)
pybamm/expression_tree/concatenations.py	98.13% <ø> (+0.68%)	⬆️
pybamm/expression_tree/exceptions.py	100.00% <ø> (ø)
... and 322 more

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[brosaplanella]

Looks good, thanks Rob! Just see my comment on the commented line.

[brosaplanella]

I am confused: the comment says it should be the transpose but below it is not transposed

[rtimms]

In the test we do, e.g., np.testing.assert_array_almost_equal(qp_data.T, phi_n[:, :, 0]) so that qp_data is transposed