Revert "fix: enable Layer 1 keepalives by default. Ref #2975"

This reverts commit e4c25549f0.

gns3server/compute/iou/iou_vm.py

@@ -192,7 +192,7 @@ class IOUVM(KernelDatapathMixin, BaseNode):
         self._private_config = ""
         self._ram = 1024  # Megabytes
         self._application_id = application_id
-        self._l1_keepalives = True
+        self._l1_keepalives = False
 
         # Kernel datapath (see KernelDatapathMixin): one persistent TAP per
         # Ethernet bay/unit, opened and held by uBridge's iol_bridge while a

gns3server/schemas/controller/templates/iou_templates.py

@@ -38,7 +38,7 @@ class IOUTemplateBase(TemplateBase):
     startup_config: Optional[str] = Field("iou_l3_base_startup-config.txt", description="Startup-config of IOU")
     private_config: Optional[str] = Field("", description="Private-config of IOU")
     l1_keepalives: Optional[bool] = Field(
-        True,
+        False,
         description="Enable Layer 1 keepalives so IOU interfaces report accurate link state",
     )
     console_type: Optional[ConsoleType] = Field(ConsoleType.telnet, description="Console type")