Documentation(864188): Fixed the issues in the Blazor ComboBox Getting Started UG

[kathiravan4982]

Description

Documentation(864188): Fixed the following issues in the Blazor ComboBox Getting Started UG documentation:

• Updated the Microsoft Templates reference URL to deep-link the "Blazor project templates and template options" section on Microsoft Learn across all three Getting Started pages.
• Updated the Interactivity location reference URL to deep-link the "Interactivity location" section on Microsoft Learn in the WebApp and Server App Getting Started pages.
• Added the required Syncfusion.Blazor.DropDowns namespace and the complete @code block to the Custom values and Configure the popup list code samples in all three Getting Started pages so the samples match the live Blazor Playground preview samples.

Code Studio usage(Mandatory)

• Code Studio used in this PR/MR?

  • Yes
  • No

• If Yes: Primary use (choose one)

  • Generate new content
  • Refactor/improve existing content
  • Review assistance (explanations/summaries)
  • Other:

• Outcome

  • Saved time
  • Neutral
  • Cost time

• If “Cost time” explain in short (1 or 2 lines):

Type of Change

• New documentation page
• Update to existing documentation
• Bug fix (broken links, typos, formatting issues)
• Structural change (folders, navigation, index)
• Content improvement (clarity, examples, screenshots)
• Other (please describe):

Reviewer Checklist (Mandatory)

• Reviewed the provided Code Studio usages related information
• Content changes follow UG/Documentation guidelines
• All provided information reviewed and verified
• Links and previews checked

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: 864188-ComboBoxUG-Hf

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: 864188-ComboBoxUG-Hf
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 0
MD File Encoding Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0