[metrics sdk]: verify and enforce attribute limits

[dyladan]

At this time, metric attributes are expected to use the same limits as the common attributes (trace):

• sdk attribute limits spec: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#attribute-limits
• attribute limits spec: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/common.md#attribute-limits

[pichlermarc]

At this time, the linked spec document mentions that metric attributes are exempt from the common rules of attribute limits. So I guess this is not needed right now.