fix(sidenav): remove dependency on OverlayModule

Removes the dependency between the sidenav and the CDK overlay, because the overlay isn't being used for anything.

Author: crisbeto

src/lib/sidenav/BUILD.bazel

@@ -14,7 +14,6 @@ ng_module(
     "//src/cdk/bidi",
     "//src/cdk/coercion",
     "//src/cdk/keycodes",
-    "//src/cdk/overlay",
     "//src/cdk/scrolling",
     "@rxjs",
   ],

src/lib/sidenav/sidenav-module.ts

@@ -7,7 +7,6 @@
  */
 
 import {A11yModule} from '@angular/cdk/a11y';
-import {OverlayModule} from '@angular/cdk/overlay';
 import {CommonModule} from '@angular/common';
 import {NgModule} from '@angular/core';
 import {MatCommonModule} from '@angular/material/core';
@@ -27,7 +26,6 @@ import {
     CommonModule,
     MatCommonModule,
     A11yModule,
-    OverlayModule,
     ScrollDispatchModule,
     PlatformModule,
   ],