fix(paste): only record a paste when it's from RPC (#30491)

Problem:  When using nvim_paste in a mapping during a macro recording,
          both the mapping and the paste are recorded, causing the paste
          to be performed twice when replaying the macro.
Solution: Only record a paste when it is from RPC.

Unfortunately this means there is no way for a script to make a recorded
paste. A way to enable that can be discussed later if there is need.

test/functional/api/vim_spec.lua

@@ -1358,6 +1358,13 @@ describe('API', function()
         test_paste_repeat_visual_select(true)
       end)
     end)
+    it('in a mapping recorded in a macro', function()
+      command([[nnoremap <F2> <Cmd>call nvim_paste('foo', v:false, -1)<CR>]])
+      feed('qr<F2>$q')
+      expect('foo')
+      feed('@r') -- repeating a macro containing the mapping should only paste once
+      expect('foofoo')
+    end)
     local function test_paste_cancel_error(is_error)
       before_each(function()
         exec_lua(([[