[BUG] graphscope-client: graph add_edges failed to add edge for label with same name but src_label and dst_label different

**Describe the bug**
A clear and concise description of what the bug is.

**To Reproduce**
Steps to reproduce the behavior:
Failed to add edge for label "knows" with different src_label and dst_label paris below code: (**error: label "knows" already exists**)
```shell
def test():
sess: graphscope.Session = get_default_session()
try:
sess.load_from()
graph = sess.g(directed=False, oid_type="int64_t")
# id|firstName|lastName|gender|birthday|creationDate|locationIP|browserUsed
data1 = pandas.read_csv("/tmp/testingdata/0001/person_0_0.csv", sep="|")
data2 = pandas.read_csv("/tmp/testingdata/0001/person_0_1.csv", sep="|")
comment = pandas.read_csv("/tmp/testingdata/0001/comment_0_1.csv", sep="|")

person = pandas.merge(data1, data2, on="id", how="outer")

data4 = pandas.read_csv("/tmp/testingdata/0001/person_knows_person_0_1.csv", sep="|")
data5 = pandas.read_csv("/tmp/testingdata/0001/person_likes_comment_0_0.csv", sep="|")
graph = graph.add_vertices(person, label="person")
graph = graph.add_vertices(comment, label="comment")
graph = graph.add_edges(data4, label="knows", src_label="person", dst_label="person")

graph = graph.add_edges(data5, label="likes", src_label="person", dst_label="comment")

graph = graph.add_edges(data5, label="knows", src_label="person", dst_label="comment")

# Analytical engine
# project the projected graph to simple graph.
simple_g = graph.project(vertices={"person": []}, edges={"knows": []})

context = graphscope.pagerank(simple_g, delta=0.8)

dataframe = context.to_dataframe(selector={'id': 'v.id', "result": 'r'})
print(dataframe)

print('this is the end of the program.. ')
except Exception as e:
traceback.print_exc(e)
finally:
sess.close()
```

while it's working fine with session.load_from as below:
```shell
def test2():
sess: graphscope.Session = get_default_session()
try:

# graph = sess.g(directed=False, oid_type="int64_t")
# id|firstName|lastName|gender|birthday|creationDate|locationIP|browserUsed
data1 = pandas.read_csv("/tmp/testingdata/0001/person_0_0.csv", sep="|")
data2 = pandas.read_csv("/tmp/testingdata/0001/person_0_1.csv", sep="|")
comment = pandas.read_csv("/tmp/testingdata/0001/comment_0_1.csv", sep="|")

person = pandas.merge(data1, data2, on="id", how="outer")

data4 = pandas.read_csv("/tmp/testingdata/0001/person_knows_person_0_1.csv", sep="|")
data5 = pandas.read_csv("/tmp/testingdata/0001/person_likes_comment_0_0.csv", sep="|")

vertices = {
"person": (
Loader(
person, header_row=True, delimiter="|"
),
[
"firstName",
"lastName",
"gender",
"birthday",
"creationDate",
"locationIP",
"browserUsed",
],
"id",
),
"comment": (
Loader(
comment, header_row=True, delimiter="|"
),
None,
"id",
)
}
edges = {
"knows": [
(
Loader(
data4,
header_row=True,
delimiter="|",
),
["creationDate"],
("Person.id", "person"),
("Person.id2", "person"),
),
(
Loader(
data4,
header_row=True,
delimiter="|",
),
["creationDate"],
("Person.id", "person"),
("Person.id2", "comment"),
)
],
"likes": [
(
Loader(
data5,
header_row=True,
delimiter="|",
),
None,
("Person.id", "person"),
("Comment.id", "comment"),
)
]
}
graph = sess.load_from(vertices=vertices, edges=edges)
# Analytical engine
# project the projected graph to simple graph.
simple_g = graph.project(vertices={"person": []}, edges={"knows": []})

context = graphscope.pagerank(simple_g, delta=0.8)

dataframe = context.to_dataframe(selector={'id': 'v.id', "result": 'r'})
print(dataframe)

print('this is the end of the program.. ')
except Exception as e:
traceback.print_exc(e)
finally:
sess.close()
```

**Expected behavior**
A clear and concise description of what you expected to happen.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Environment (please complete the following information):**
- GraphScope version: [v0.16.0]
- OS: [MacOS(M1)]
- Version [12.3]
- Kubernetes Version [1.22.8]

**Additional context**
Add any other context about the problem here.