[Fluent] Fix ComboBox Style

[siagupta0202]

Description

This is a subissue to track the issues related to ComboBox apart from the ones mentioned in the parent issue #10393. Currently we have the following issues:

• Fluent2 ComboBox Missing Scrollbars #10571
• Fluent2 Editable ComboBox Issues #10470
• Fluent2: Controls Are NOT Designed for Custom Height #10359
• Missing resource as mentioned in Fluent2 ComboBox Missing Scrollbars #10571

[danielkornev]

Adding this task:
#10629

@dipeshmsft 🙏🙏🙏🙏🙏🙏🙏🙏