Accessibility issues with Combo Box

[pankajpandey01]

Describe the bug
Accessibility issues on shadow dom input element

1. Required ARIA attribute not present: aria-expanded
2. aria-label attribute does not exist or is empty
3. aria-labelledby attribute does not exist, references elements that do not exist or references elements that are empty
4. Form element does not have an implicit (wrapped)
5. Form element does not have an explicit
6. Element has no title attribute or the title attribute is empty

To reproduce
Steps to reproduce the behavior:

1. Go to 'https://sap.github.io/ui5-webcomponents/playground/components/ComboBox/'
2. Select on of the sample
3. Use Chrome Axe plugin to see all critical and serious issue (Screenshot attached)

Expected behavior
There should not be a11y issues in combo box.

Screenshots

Context

• Combo Box version v1.0.0-rc.6
• OS/Platform: {MacOS}