🤝 Roll Custom Tabs Library version.

It appears that changes to custom-tabs-client code are not synced to
https://github.com/GoogleChrome/custom-tabs-client until they are
included in Chrome's DEPS.

This rolls the custom tabs client code to include fixes to a Trusted
Web Activity utility class and to make it build with Java 8 (it was
previously using Java 8 features, so technically this is a fix).

Bug: 854603
Change-Id: I0937d2ed077cdf716293182c8b1bac6ef0895534
Reviewed-on: https://chromium-review.googlesource.com/c/1337489Reviewed-by: Michael van Ouwerkerk <mvanouwerkerk@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609683}

DEPS

@@ -671,7 +671,7 @@ deps = {
   },
 
   'src/third_party/custom_tabs_client/src': {
-      'url': Var('chromium_git') + '/custom-tabs-client.git' + '@' + 'c813ed8fcc4ece1838dba8dddf6d8ca39d6c6785',
+      'url': Var('chromium_git') + '/custom-tabs-client.git' + '@' + '4c092f007199e64798a0c6d48c4a847758392952',
       'condition': 'checkout_android',
   },