Fix filtering for tagged lambda functions with "lambda:function"

[kirberich]

The resource group tagging api get_resources method doesn't allow for filtering for lambda functions using a lambda:function resource type filter, it's only checking for lambda - this adds support for that, in the same way it's done for other kinds of resources

First commit has the failing test:

        resp = rtapi.get_resources(ResourceTypeFilters=["lambda:function"])
>       assert_response(resp, [circle_arn, rectangle_arn])

tests/test_resourcegroupstaggingapi/test_resourcegroupstaggingapi.py:708: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

response = {'ResourceTagMappingList': [], 'ResponseMetadata': {'HTTPHeaders': {'date': 'Mon, 13 May 2024 11:09:28 GMT', 'server':...Hw8'}, 'HTTPStatusCode': 200, 'RequestId': 'YRtMzouuFVfnMx5K4jhUXR0Of8m1k7vdSQHKA1JcQSdRgKLvQHw8', 'RetryAttempts': 0}}
expected_arns = ['arn:aws:lambda:us-west-2:123456789012:function:lambda-tag-value-1', 'arn:aws:lambda:us-west-2:123456789012:function:lambda-tag-value-2']

    def assert_response(response, expected_arns):
        results = response.get("ResourceTagMappingList", [])
        resultArns = []
        for item in results:
            resultArns.append(item["ResourceARN"])
        for arn in resultArns:
            assert arn in expected_arns
        for arn in expected_arns:
>           assert arn in resultArns
E           AssertionError: assert 'arn:aws:lambda:us-west-2:123456789012:function:lambda-tag-value-1' in []