Add tests for label limits specifically for label_limit, label_name_length_limit & label_value_length_limit configuration values for Prometheus Receiver

[mustafain117]

Is your feature request related to a problem? Please describe.
We want to ensure that Prometheus receiver honors label_limit, label_name_length_limit & label_value_length_limit configuration values.

Describe the solution you'd like
We propose the following solution:

• Add one test for label_limit configuration
• Add one test for label_name_length_limit configuration
• Add one test for label_value_length_limit configuration

Each test will:

• Set label_limit, label_name_length_limit & label_value_length_limit in the config for Prometheus receiver
• For the positive test case, the prometheus receiver scrapes metrics which are within the defined limits for label_limit, label_name_length_limit & label_value_length_limit
  • Assert scrape is successful
• For the negative test case, the prometheus receiver scrapes metrics which do not conform to the defined limits
  • for e.g metrics with number of labels greater than label_limit
  • Assert scrape is unsuccessful

Additional context
Related to: open-telemetry/wg-prometheus#57

CC: @alolita @Aneurysm9

[mustafain117]

@alolita please assign this to me!