Work around vsce refusal to publish extensions with proposed API

- enabledApiProposals is removed, and enablement can be controlled at
  the platform level

Signed-off-by: Roland Grunberg <rgrunber@redhat.com>

Author: rgrunber

package.json

@@ -9,9 +9,6 @@
   "publisher": "redhat",
   "bugs": "https://github.com/redhat-developer/vscode-java/issues",
   "preview": false,
-  "enabledApiProposals": [
-    "documentPaste"
-  ],
   "capabilities": {
     "untrustedWorkspaces": {
       "supported": "limited",