chore(ec2): add Windows Server 2025 to WindowsVersion enum (#33499)

### Issue # (if applicable)
Closes #33497 (aws-ec2): Add Windows Server 2025 to WindowsVersion enum

### Reason for this change

The AWS License Manager team requires Windows Server 2025 support in the WindowsVersion enum to build production-ready EC2 image pipelines.

### Description of changes
Added new enum values in packages/@aws-cdk/aws-ec2/lib/windows-versions.ts:

```
WINDOWS_SERVER_2025_ENGLISH_FULL_BASE = 'Windows_Server-2025-English-Full-Base',
WINDOWS_SERVER_2025_ENGLISH_CORE_BASE = 'Windows_Server-2025-English-Core-Base'
```

- No breaking changes introduced
- Maintains consistent naming convention with existing enum values
- Describe any new or updated permissions being added
- No new IAM permissions are required for this change as it only extends the existing enum with additional values.

### Description of how you validated changes

**Existing Unit Tests:**

- Ran all existing unit tests to ensure no regressions
- Confirmed all tests pass successfully with the new enum values added

**Manual Testing:**

- Tested in development environment
- Verified correct AMI resolution using the new enum values

**Checklist**

[x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)
[x] My code adheres to the [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)
[ ] Added new unit tests (No new tests added, verified against existing tests)
[ ] Added integration tests (Manual testing performed)
[x] Followed existing enum naming conventions

packages/aws-cdk-lib/aws-ec2/lib/windows-versions.ts

@@ -417,4 +417,16 @@ export enum WindowsVersion {
   WINDOWS_SERVER_2022_JAPANESE_FULL_SQL_2022_STANDARD = 'Windows_Server-2022-Japanese-Full-SQL_2022_Standard',
   WINDOWS_SERVER_2022_JAPANESE_FULL_SQL_2022_ENTERPRISE = 'Windows_Server-2022-Japanese-Full-SQL_2022_Enterprise',
   /** 2022 - End */
+  /** 2025 - Start */
+  WINDOWS_SERVER_2025_CHINESE_SIMPLIFIED_FULL_BASE = 'Windows_Server-2025-Chinese_Simplified-Full-Base',
+  WINDOWS_SERVER_2025_CHINESE_TRADITIONAL_FULL_BASE = 'Windows_Server-2025-Chinese_Traditional-Full-Base',
+  WINDOWS_SERVER_2025_ENGLISH_CORE_BASE = 'Windows_Server-2025-English-Core-Base',
+  WINDOWS_SERVER_2025_ENGLISH_FULL_BASE = 'Windows_Server-2025-English-Full-Base',
+  WINDOWS_SERVER_2025_ENGLISH_FULL_SQL_2022_ENTERPRISE = 'Windows_Server-2025-English-Full-SQL_2022_Enterprise',
+  WINDOWS_SERVER_2025_ENGLISH_FULL_SQL_2022_EXPRESS = 'Windows_Server-2025-English-Full-SQL_2022_Express',
+  WINDOWS_SERVER_2025_ENGLISH_FULL_SQL_2022_STANDARD = 'Windows_Server-2025-English-Full-SQL_2022_Standard',
+  WINDOWS_SERVER_2025_ENGLISH_FULL_SQL_2022_WEB = 'Windows_Server-2025-English-Full-SQL_2022_Web',
+  WINDOWS_SERVER_2025_JAPANESE_FULL_BASE = 'Windows_Server-2025-Japanese-Full-Base',
+  WINDOWS_SERVER_2025_KOREAN_FULL_BASE = 'Windows_Server-2025-Korean-Full-Base',
+  /** 2025 - End */
 }