GHA: use more Ninja
Use it for AmigaOS, Android, dl-mingw 7.3.0 and 6.4.0 Windows builds.
Also drop explicit ninja installs.
dl-mingw:
Before:
7.3.0: https://github.com/curl/curl/actions/runs/
14617346216/job/
41008536465
6.4.0: https://github.com/curl/curl/actions/runs/
14617346216/job/
41008540878
After:
7.3.0: https://github.com/curl/curl/actions/runs/
14617983032/job/
41010584040?pr=17153
6.4.0: https://github.com/curl/curl/actions/runs/
14617983032/job/
41010586490?pr=17153
Follow-up to
a36655224356c10d70bcc566ce60f82af795ca90 #17115
Ref: https://github.com/actions/runner-images/issues/11391
Closes #17153
projects / thirdparty / curl.git / commit
