Enable typescript strictNullChecks

[fityannugroho]

PR Checklist

Please check if your PR fulfills the following requirements:

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• The commit message follows our Contributing Guidelines
• Tests for the changes have been added (optional, for bug fixes or features)
• Docs have been added / updated (optional, for bug fixes or features)

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What kind of change does this PR introduce?

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• Bug fix
• Feature
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• Refactoring (no functional changes, no api changes)
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What is the current behavior?

Please describe the current behavior that you are modifying, or link to a relevant issue.

Issue Number: #465

What is the new behavior?

This pull request includes changes to improve error handling, type safety, and code readability across several files in the project. The most important changes include adding error handling for missing package versions, improving type assertions, and enhancing null safety in various functions.

Error Handling Improvements:

• prisma/seeder.ts: Added error handling to check if the idn-area-data package is installed before proceeding with log generation.

Type Safety Enhancements:

• src/app.module.ts: Added type assertions to ensure the correct types are used for throttle configuration values.
• src/main.ts: Added type assertion to ensure the version is a string when setting up the API documentation with Swagger.

Null Safety Enhancements:

• src/common/decorator/EqualsAny.ts: Improved null safety by using optional chaining and nullish coalescing operators in the EqualsAnyConstraint class.
• src/common/decorator/IsNotSymbol.ts: Enhanced null safety in the IsNotSymbolConstraint class by using optional chaining and nullish coalescing operators. [1] [2]

Code Readability Improvements:

• src/common/utils/coordinate.ts: Refactored the convertCoordinate function to improve readability and added error handling for invalid coordinate formats.
• src/island/island.service.ts: Added type assertion to ensure the province is not null when finding a unique province.

Other information

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