refactor(material/list): simplify structural styles (#29383)

Reworks the structural styles for the list to make them smaller and easier to maintain.

Author: crisbeto

src/material/list/BUILD.bazel

@@ -42,6 +42,15 @@ sass_library(
     ],
 )
 
+sass_library(
+    name = "inherited_structure_scss_lib",
+    srcs = ["_list-inherited-structure.scss"],
+    deps = [
+        "//src/cdk:sass_lib",
+        "//src/material/core:core_scss_lib",
+    ],
+)
+
 sass_library(
     name = "list_scss_lib",
     srcs = glob(["**/_*.scss"]),
@@ -59,6 +68,7 @@ sass_binary(
     src = "list.scss",
     deps = [
         ":hcm_indicator_scss_lib",
+        ":inherited_structure_scss_lib",
         "//:mdc_sass_lib",
         "//src/material/core:core_scss_lib",
     ],