[fix] Typos and links to issue tracker on sample_testing.sql. Fixes #4454

Incorrect link to issue tracker

Update sample_testing.sql

Incorrect link to issue tracker.

Update sample_testing.sql

Incorrect link to issue tracker

Update sample_testing.sql

Typo fixed and corrected links to issue tracker.

Update sample_testing.sql

Fixed typo and corrected links to issue tracker.

Update sample_testing.sql

Fixed typo and corrected link to issue tracker