#0: skip N300 tests for ubench CI (#18284)

### Ticket
Link to Github Issue

### Problem description
Provide context for the problem.

### What's changed
Describe the approach used to solve the problem.
Summarize the changes made and its impact.

### Checklist
- [ ] ubench
https://github.com/tenstorrent/tt-metal/actions/runs/13534090777

tests/tt_metal/microbenchmarks/ethernet/test_fabric_edm_bandwidth.py

@@ -73,6 +73,9 @@ def run_fabric_edm(
                 {packet_size} "
     rc = os.system(cmd)
     if rc != 0:
+        if os.WEXITSTATUS(rc) == 1:
+            pytest.skip("Skipping test because it only works with T3000")
+            return
         logger.info("Error in running the test")
         assert False
 

tests/ttnn/unit_tests/gtests/ccl/test_fabric_edm.cpp

@@ -14,6 +14,12 @@ int main(int argc, char** argv) {
     std::size_t line_size = std::stoi(argv[arg_idx++]);
     std::size_t packet_payload_size_bytes = std::stoi(argv[arg_idx++]);
 
+    uint32_t test_expected_num_devices = 8;
+    if (tt::tt_metal::GetNumAvailableDevices() < test_expected_num_devices) {
+        tt::log_warning("This test can only be run on T3000 devices");
+        return 1;
+    }
+
     WriteThroughputStabilityTestWithPersistentFabricParams params;
     params.line_sync = line_sync;
     params.line_size = line_size;