docs: drop the defunct pylops from the source-install requirements

Removes the whole "For unit tests to pass you will also need the following
optional requirements" stanza from the Building-Only-PyAutoCTI section: with
pynufft gone in the previous commit, `pip install pylops==1.11.1` was the only
line left, and pylops is defunct.

Same evidence as for pynufft: nothing in this repo imports or references pylops
(the only other hit is paper/paper.bib, a published record), pyproject's
`optional` extra is ["numba"], and CI installs no pylops while 270 of 271 tests
pass — the single failure is an unrelated autoarray mask-shape guard on main.

The sentence and its code-block go together; leaving the heading with an empty
code-block would be invalid RST.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Q7kFdoYcD6wnTifNXV5T98

Author: James Nightingale

docs/installation/source.rst

@@ -51,12 +51,6 @@ Next, install the optional dependency numba via pip  (see `this link <https://py
 
     pip install numba
 
-For unit tests to pass you will also need the following optional requirements:
-
-.. code-block:: bash
-
-    pip install pylops==1.11.1
-
 If you are using a ``conda`` environment, add the source repository as follows:
 
 [NOTE: Certain versions of conda use the command ``conda develop`` (without a dash) instead of those shown below.]