[ci] Mark Fedora 43 and Ubuntu 25.10 as non-special builds

Ubuntu 25.10 is already released, and Fedora 43 will be released in 10
days.

Author: guitargeek

.github/workflows/root-ci.yml

@@ -380,7 +380,6 @@ jobs:
             overrides: ["CMAKE_CXX_STANDARD=23"]
           - image: fedora43
             overrides: ["CMAKE_CXX_STANDARD=23"]
-            is_special: true
           - image: alma8
           - image: alma9
             overrides: ["CMAKE_BUILD_TYPE=Debug"]
@@ -392,7 +391,6 @@ jobs:
           - image: ubuntu2504
             overrides: ["CMAKE_CXX_STANDARD=23"]
           - image: ubuntu2510
-            is_special: true
             overrides: ["CMAKE_CXX_STANDARD=23"]
           - image: debian125
             overrides: ["CMAKE_CXX_STANDARD=20", "dev=ON", "CMAKE_CXX_FLAGS=-Wsuggest-override"]