SM-1227: Improved error messages on failures

🎟️ Tracking

Improve error messages on failures.

action.yml: Added default value to base_url, since the docs specifies that all required: false inputs needs a default value.
src/main.ts:
- access_token input is required - consistency with action.yml
- Added error message from BitwardenClient.loginWithAccessToken response into the error handling.
- Debug logging when GH Action runs in debug.
- Refactoring
- Unit Tests coverage
src/parser.ts:
- Added parsing error messages from various parsing error scenarios as part into error handling.
- Unit Test coverage

Contributor guidelines followed
All formatters and local linters executed and passed
Written new unit and / or integration tests where applicable
Protected functional changes with optionality (feature flags)
Used internationalization (i18n) for all UI strings
CI builds passed
Communicated to DevOps any deployment requirements
Updated any necessary documentation (Confluence, contributing docs) or informed the documentation team

👍 (:+1:) or similar for great changes
📝 (:memo:) or ℹ️ (:information_source:) for notes or general info
❓ (:question:) for questions
🤔 (:thinking:) or 💭 (:thought_balloon:) for more open inquiry that's not quite a confirmed issue and could potentially benefit from discussion
🎨 (:art:) for suggestions / improvements
❌ (:x:) or ⚠️ (:warning:) for more significant problems or concerns needing attention
🌱 (:seedling:) or ♻️ (:recycle:) for future improvements or indications of technical debt
⛏ (:pick:) for minor or nitpick changes