[core] Strengthen RawExpression-as-arg test

Exercise the actual CallExpression(..., RawExpression) pattern that components use for passing raw arguments. The previous test used RawStatement filler which didn't exercise the detection path we wanted to assert doesn't trigger.

tests/unit_tests/test_core.py

@@ -9,6 +9,7 @@ from strategies import mac_addr_strings
 from esphome import const, core
 from esphome.cpp_generator import (
     AssignmentExpression,
+    CallExpression,
     ComponentMarker,
     ExpressionStatement,
     IIFEUnsafeStatement,
@@ -1068,15 +1069,20 @@ def test_cpp_main_section_raw_expression_as_call_arg_still_sub_splits() -> None:
     # `var.set_program(RawExpression("&foo"))`) produces
     # `ExpressionStatement(CallExpression(..., RawExpression))` — the
     # outer expression is a CallExpression, not a RawExpression, so
-    # the group is still sub-splittable.
+    # the group is still sub-splittable. Exercise this with actual
+    # CallExpression-wrapping-RawExpression statements filling the
+    # group past the 50-statement cap.
     target = core.EsphomeCore()
     stmts: list = [ComponentMarker("rp2040_pio_led_strip")]
-    # Emit >50 plain statements with one being an ExpressionStatement
-    # wrapping a non-RawExpression inner (RawStatement for simplicity
-    # here — the real codegen wraps a CallExpression).
-    stmts.extend(RawStatement(f"s{i}();") for i in range(120))
+    stmts.extend(
+        ExpressionStatement(
+            CallExpression(MockObj(f"var_{i}.set_program"), RawExpression("&foo"))
+        )
+        for i in range(120)
+    )
     target.main_statements = stmts
     out = target.cpp_main_section
+    # 120 statements / 50-cap -> 3 sub-chunks.
     assert out.count("[]() {") == 3