test : added unit tests for Database execute/fetchone/fetchall/executescript methods

[tmdeveloper007]

Closes #1726.

Summary of What Has Been Done:
Created testing/backend/unit/test_database.py covering the basic Database class methods not tested by existing test files (test_database_connection.py and test_database_workflow_versions.py).

Changes Made:

• New file: testing/backend/unit/test_database.py - 17 unit tests covering:
  • Database.execute: INSERT/UPDATE/DELETE rowcount, auto-commit, zero-rowcount cases
  • Database.fetchone: returns dict, returns None for missing, dict key access
  • Database.fetchall: returns list of dicts, handles zero rows, aggregates
  • Database.executescript: creates tables, auto-commits
  • Error handling: syntax errors propagate as exceptions

Impact it Made:

• Coverage: adds tests for Database methods not covered by existing workflow/version tests
• Reliability: ensures execute/fetch methods work correctly for all return cases
• Completeness: fills the gap in Database class method testing

Note: This task is being handled by tmdeveloper007 — please assign to that account when picking it up.

[utksh1]

Closing: this PR is part of the same mass template-generated low-value test batch pattern. The PRs use repetitive boilerplate bodies, copy-pasted structures, and in several cases manufacture tiny helpers or duplicate existing coverage rather than contributing one focused, meaningful improvement. Please submit a smaller, genuinely curated PR if you want to work on one concrete test gap.