chromium: don't enable the labs button

It has nothing that interesting and is just distraction.

etc/opt/chromium/policies/managed/README.md

@@ -151,7 +151,8 @@ Incompatible with any actual DoH policy.
 
 ## `doh-dns0.json`
 
-Simply enables DNS-over-HTTPS with DNS0.eu
+Simply enables DNS-over-HTTPS with DNS0.eu. `automatic` means downgrade is
+allowed (the system resolver is encrypted), `secure` would lock it.
 
 ## `enable-ech-ocsp.json`
 

etc/opt/chromium/policies/managed/doh-dns0.json

@@ -1,4 +1,4 @@
 {
-  "DnsOverHttpsMode": "secure",
+  "DnsOverHttpsMode": "automatic",
   "DnsOverHttpsTemplates": "https://dns0.eu"
 }

etc/opt/chromium/policies/managed/enable-home-labs.json

@@ -1,4 +0,0 @@
-{
-  "BrowserLabsEnabled": true,
-  "ShowHomeButton": true
-}

etc/opt/chromium/policies/managed/enable-home.json

@@ -0,0 +1,3 @@
+{
+  "ShowHomeButton": true
+}