Convert team_number to use string_view

Remove StringToNumber while we are here since it has been replaced by
absl and is used in exactly 1 spot.

Change-Id: Idfdb7876208608819b855c42f930a7a10ada3855
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/aos/network/BUILD b/aos/network/BUILD
index e6ff5af..067ae35 100644
--- a/aos/network/BUILD
+++ b/aos/network/BUILD
@@ -105,8 +105,8 @@
     ],
     target_compatible_with = ["@platforms//os:linux"],
     deps = [
-        "//aos/util:string_to_num",
         "@com_github_google_glog//:glog",
+        "@com_google_absl//absl/strings",
     ],
 )