Don't consider indirect dependencies when calculating SCCs (#19903)

SCC construction should only need to consider import dependencies, since
indirect dependencies are not available during non-incremental runs, and
we want SCCs to be identical in incremental and non-incremental runs. This
may improve performance slightly and will make mypy more robust in case
there are extra indirect dependencies (see #19906).

Author: JukkaL

mypy/build.py

@@ -3488,7 +3488,7 @@ def process_stale_scc(graph: Graph, scc: list[str], manager: BuildManager) -> No
 
 
 def sorted_components(
-    graph: Graph, vertices: AbstractSet[str] | None = None, pri_max: int = PRI_ALL
+    graph: Graph, vertices: AbstractSet[str] | None = None, pri_max: int = PRI_INDIRECT
 ) -> list[AbstractSet[str]]:
     """Return the graph's SCCs, topologically sorted by dependencies.