fix(tapd): fix errors when configrating scopes

[d4x1]

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Summary

What does this PR do?
TAPD's api return something like:

{
    "status": 1,
    "data":
    [
        {
            "Workspace":
            {
                "id": "55850509",
                "name": "xx",
                "pretty_name": "55850509",
                "description": "",
                "status": "normal",
                "parent_id": "1",
                "secrecy": "0",
                "created": "2020-11-15 16:34:28",
                "creator_id": "1093132487",
                "creator": "abc",
                "begin_date": null,
                "end_date": null,
                "member_count": 28
            }
        }
    ],
    "info": "success"

id and parent_id is a string which can be parsed to uint64. Devlake's code regard these two fields as uint64.
So I extract type StringUint64, adapt to TAPD's API resp.

Does this close any open issues?

Closes N/A

Screenshots

Include any relevant screenshots here.

Other Information

Any other information that is important to this PR.

[klesh]

according https://github.com/mitchellh/mapstructure/blob/main/mapstructure_examples_test.go#L123 mapstructure should support decoding string into int. This should not be needed, please confirm if it is necessary.

[d4x1]

#6239 fix this problem in a simple way.