comment out unstable proposal v2_6 testcase (openvinotoolkit#23742)

### Details:
 - *comment out the PDPD proposal v2_6 testcase*
 
### Tickets:
 - *130605*

src/frontends/paddle/tests/op_fuzzy.cpp

@@ -247,7 +247,7 @@ static const std::vector<std::string> models{
     std::string("generate_proposals_v2_4"),
     // ticket 130605: actual res value is not close
     // std::string("generate_proposals_v2_5"),
-    std::string("generate_proposals_v2_6"),
+    // std::string("generate_proposals_v2_6"),
     // greater_equal_big_int64(failure due to CPU inference),
     std::string("greater_equal_big_int64"),
     std::string("greater_equal_float32"),

src/frontends/paddle/tests/test_models/gen_scripts/generate_generate_proposal_v2.py

@@ -150,6 +150,8 @@ def generate_proposals_v2(name: str, input_data: dict, attr: dict):
     '''
 
     # test case 6
+    '''
+    TODO: ticket 130605
     input_name = "generate_proposals_v2_6"
     input_data["scores"] = np.random.rand(2, 6, 10, 8).astype('float32')
     input_data["bbox_deltas"] = np.random.rand(2, 24, 10, 8).astype('float32')
@@ -162,3 +164,4 @@ def generate_proposals_v2(name: str, input_data: dict, attr: dict):
     attr["post_nms_top_n"] = 60
 
     generate_proposals_v2(input_name, input_data, attr)
+    '''