Revert "Bump setuptools from 73.0.1 to 75.7.0 in /.ci"

This reverts commit 23358ec2796c606b580a5fe41ffaf2510a9fd3fe.

Bots failing.
diff --git a/.ci/requirements.txt b/.ci/requirements.txt
index da1d5db..3072729 100644
--- a/.ci/requirements.txt
+++ b/.ci/requirements.txt
@@ -249,7 +249,7 @@
     # via gcovr
 
 # The following packages are considered to be unsafe in a requirements file:
-setuptools==75.7.0 \
-    --hash=sha256:84fb203f278ebcf5cd08f97d3fb96d3fbed4b629d500b29ad60d11e00769b183 \
-    --hash=sha256:886ff7b16cd342f1d1defc16fc98c9ce3fde69e087a4e1983d7ab634e5f41f4f
+setuptools==73.0.1 \
+    --hash=sha256:b208925fcb9f7af924ed2dc04708ea89791e24bde0d3020b27df0e116088b34e \
+    --hash=sha256:d59a3e788ab7e012ab2c4baed1b376da6366883ee20d7a5fc426816e3d7b1193
     # via -r requirements.in