@W-20992906: [Android] Remove welcome from default server list in master (#2825)

Author: JohnsonEricAtSalesforce

libs/SalesforceSDK/res/xml/servers.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <servers>
     <server name="Production" url="https://login.salesforce.com" />
-    <server name="Welcome" url="https://welcome.salesforce.com/discovery" />
     <server name="Sandbox" url="https://test.salesforce.com" />
 </servers>

native/NativeSampleApps/RestExplorer/res/xml/servers.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <servers>
     <server name="Production" url="https://login.salesforce.com" />
-    <server name="Welcome" url="https://welcome.salesforce.com/discovery" />
     <server name="Sandbox" url="https://test.salesforce.com" />
     <server name="SDK Production" url="https://mobilesdk.my.salesforce.com" />
 </servers>