fix(linux): apt_update_upgrade left dependency-driven updates pending

Plain "apt-get upgrade" refuses to install or remove packages even when
a newer version requires it, silently holding those updates back —
switched to "apt-get full-upgrade" so VM-provisioning bootstrap actually
finishes with nothing left to update.

napalm_linux/linux.py

@@ -1889,7 +1889,12 @@ class LinuxDriver(OSDriver):
         raise NotImplementedError(f"Unknown action: {action!r}")
 
     def _action_apt_update_upgrade(self) -> DeviceActionResultDict:
-        """Refresh the apt cache and upgrade all packages (apt-based systems only)."""
+        """Refresh the apt cache and fully upgrade all packages (apt-based systems only).
+
+        Uses full-upgrade (not plain upgrade) — plain "apt-get upgrade" refuses
+        to install/remove packages even when required to satisfy a newer
+        version's dependencies, silently leaving those updates pending.
+        """
         if self._pkg_manager != "apt":
             return {
                 "success": True,
@@ -1913,7 +1918,7 @@ class LinuxDriver(OSDriver):
             out = self._sudo("apt-get update -y 2>&1", read_timeout=90)
             lines.append(f"[update] {out.strip()[-300:]}")
             out = self._sudo(
-                "DEBIAN_FRONTEND=noninteractive apt-get upgrade -y 2>&1", read_timeout=240
+                "DEBIAN_FRONTEND=noninteractive apt-get full-upgrade -y 2>&1", read_timeout=240
             )
             lines.append(f"[upgrade] {out.strip()[-300:]}")
             return {"success": True, "output": "\n".join(lines)}

tests/test_linux.py

@@ -776,7 +776,9 @@ class TestActionAptUpdateUpgrade:
         assert "[upgrade]" in result["output"]
         update_call, upgrade_call = mock_sudo.call_args_list
         assert "apt-get update" in update_call.args[0]
-        assert "apt-get upgrade" in upgrade_call.args[0]
+        # full-upgrade (not plain upgrade) — plain upgrade silently holds back
+        # packages whose newer version needs to install/remove dependencies.
+        assert "apt-get full-upgrade" in upgrade_call.args[0]
 
     def test_exception_during_upgrade_returns_failure(self, driver):
         driver._pkg_manager = "apt"