position-area: span-all: Mark Firefox bug as fixed, consistently (#29628)

Issue: #28761
Issue: https://bugzilla.mozilla.org/show_bug.cgi?id=2008537

Author: ddbeck

css/properties/position-area.json

@@ -1124,11 +1124,17 @@
               ],
               "chrome_android": "mirror",
               "edge": "mirror",
-              "firefox": {
-                "version_added": "147",
-                "partial_implementation": true,
-                "notes": "Using `span-all` unexpectedly allows the anchored box to overflow the viewport, obscuring content. Use `place-self: anchor-center` as a workaround. See [bug 2008537](https://bugzil.la/2008537)."
-              },
+              "firefox": [
+                {
+                  "version_added": "148"
+                },
+                {
+                  "version_added": "147",
+                  "version_removed": "148",
+                  "partial_implementation": true,
+                  "notes": "Using `span-all` unexpectedly allows the anchored box to overflow the viewport, obscuring content. Use `place-self: anchor-center` as a workaround. See [bug 2008537](https://bugzil.la/2008537)."
+                }
+              ],
               "firefox_android": "mirror",
               "oculus": "mirror",
               "opera": "mirror",