https://datadoghq.atlassian.net/browse/SVLS-8095

## Overview
Tag parsing previously used split(':') which broke values containing colons like URLs (git.repository_url:https://...). Changed to usesplitn(2, ':') to split only on the first colon, preserving the rest as the value.

Changes:
 - Add parse_key_value_tag() helper to centralize parsing logic
 - Refactor deserialize_key_value_pairs to use helper
 - Refactor deserialize_key_value_pair_array_to_hashmap to use helper
 - Add comprehensive test coverage for URL values and edge cases

## Testing 
unit test and expect e2e tests to pass

Co-authored-by: tianning.li <tianning.li@datadoghq.com>