textproc/py-python-lsp-server: Fix circular dep

Both, textproc/py-python-lsp-server and textproc/py-python-lsp-black,
depend on each other. Remove black dep in lsp-server.

MFH: 2024Q4
(cherry picked from commit 8716fd92c138bf078d80191b91cdb7208a66b0ad)