Partial celery task time limit is not support

[OHeimlich]

Python 3.8

Steps to reproduce

• Create celery task with only one of the time limit soft/hard
  Or use this test to reproduce:

instrumentation/opentelemetry-instrumentation-celery/tests/test_utils.py

    def test_set_attributes_partial_timelimit_hard_limit(self):
        context = {
            "correlation_id": "44b7f305",
            "delivery_info": {"eager": True},
            "eta": "soon",
            "expires": "later",
            "hostname": "localhost",
            "id": "44b7f305",
            "reply_to": "44b7f305",
            "retries": 4,
            "timelimit": ("now", None),
            "custom_meta": "custom_value",
            "routing_key": "celery",
        }
        span = trace._Span("name", mock.Mock(spec=trace_api.SpanContext))
        utils.set_attributes_from_context(span, context)
        self.assertEqual(span.attributes.get("celery.timelimit"), ("now", ""))

What is the expected behavior?
The time limit that was specify should be instrumented

What is the actual behavior?
Exception is raised and no time limit is instrumented

[__init__.py:_translate_attributes:164] _translate_key_values(key, value)
exception.trace.1	
[exporter.py:_translate_key_values:126] return KeyValue(key=key, value=_translate_value(value))
exception.trace.2	
[ exporter.py:_translate_value:104] array_value=ArrayValue(values=[_translate_value(v) for v in value])
exception.trace.3	
[ exporter.py:<listcomp>:104] array_value=ArrayValue(values=[_translate_value(v) for v in value])
exception.trace.4	
[ exporter.py:_translate_value:119] "Invalid type {} of value {}".format(type(value), value)