Fix: Google Ads fails due to nested primary keys

[sukantaroy01]

Fixes: #181

During a proof of concept (POC) with the Google Ads source, I encountered an issue where primary keys containing periods (e.g., campaign.id, adset.id) were not being correctly handled. The root cause was that get_primary_keys did not normalize column names before checking for nested keys.

To address this, I implemented normalization of primary keys prior to the nested key check. This resolved the issue, allowing successful data collection from the Google Ads platform.

Summary by CodeRabbit

• New Features
  • Enhanced primary key processing by introducing normalization for consistency and compatibility.
• Bug Fixes
  • Corrected discrepancies in primary key formatting that could affect system integration.