[globals] Fix TemplatableFn deprecation warning for globals.set (#15733)

esphome/components/globals/__init__.py

@@ -108,8 +108,13 @@ async def globals_set_to_code(config, action_id, template_arg, args):
     full_id, paren = await cg.get_variable_with_full_id(config[CONF_ID])
     template_arg = cg.TemplateArguments(full_id.type, *template_arg)
     var = cg.new_Pvariable(action_id, template_arg, paren)
+    # Use the global's value_type alias as the lambda return type so
+    # TemplatableFn stores a direct function pointer instead of going through
+    # the deprecated converting trampoline when the value expression deduces
+    # to a different type (e.g. int literal assigned to a float global).
+    value_type = cg.RawExpression(f"{full_id.type}::value_type")
     templ = await cg.templatable(
-        config[CONF_VALUE], args, None, to_exp=cg.RawExpression, wrap_constant=True
+        config[CONF_VALUE], args, value_type, to_exp=cg.RawExpression
     )
     cg.add(var.set_value(templ))
     return var