text: Title: Replace `assert_almost_equal` with `assert_allclose`
  Body: `assert_allclose` was added to TensorLy in #420 and `assert_almost_equal` (which is currently used in many tests in TensorLy) is discouraged by [NumPy](https://numpy.org/doc/stable/reference/generated/numpy.testing.assert_almost_equal.html). We should therefore update all tests that use `assert_almost_equal` to use `assert_allclose` instead.
  
  The change should be relatively straightforward: Find a test with `assert_almost_equal`, and change to `assert_allclose`, possibly modifying the tolerance accordingly.