Override linux aarch64 python version

Author: Ariouz

.github/scripts/extract_matrix.py

@@ -43,6 +43,11 @@
     "windows-latest": ["windows", "amd64"]
 }
 
+# Override unavailable Python versions for some OS/Arch combinations
+PYTHON_VERSIONS = {
+    "ubuntu-24.04-arm": "3.12.8",
+}
+
 
 @dataclass
 class Artifact:
@@ -95,6 +100,9 @@ def python_version(self) -> str | None:
             del self.env["MX_PYTHON"]
         if "MX_PYTHON_VERSION" in self.env:
             del self.env["MX_PYTHON_VERSION"]
+            
+        if self.runs_on in PYTHON_VERSIONS:
+            python_version = PYTHON_VERSIONS[self.runs_on]
         return python_version
 
     @cached_property

ci/python-gate.libsonnet

@@ -91,9 +91,7 @@
                 MUSL_TOOLCHAIN: {name: "musl-toolchain", version: "1.0", platformspecific: true},
                 PYTHON3_HOME: {name: "python3", version: "3.12.8", platformspecific: true},
             },
-            aarch64: {
-                PYTHON3_HOME: {name: "python3", version: "3.12.8", platformspecific: true},
-            },
+            aarch64: {},
         },
         darwin: {
             common: {},