[SF][ui5-menu]: JS error when mouse over on icon area of none-icon menu item

[GongRichard]

Bug Description

Menu with icon item and none-icon item. When mouse over on icon area of none-icon menu item, there will have js error. Please fix it in 1.6.X or 1.7.0.

Expected Behavior

No js error.

Steps to Reproduce

1. Go to 'https://sap.github.io/ui5-webcomponents/playground/components/Menu/'
2. click button "Open Menu"
3. mouse over on left area of "Close" menu item
4. check console and there has js error.

Context

• UI5 Web Components version: {1.6.0}
• OS/Platform: {macOS}
• Browser: {Chrome}
• Affected component: {ui5-menu}

Log Output / Stack Trace / Screenshots

Priority

• [ ] Low
• [ ] Medium
• [x] High
• [ ] Very High

The priority indicates the severity of the issue. To set the appropriate priority consider the following criteria:

• Breaks entire application or system - High or Very High
• Accessibility issue - Medium or High
• Functional issue - Medium or High
• Visual issue - Low or Medium

Note: The priority might be re-evaluated by the issue processor.

Stakeholder Info (if applicable)

• Organization: {SAP SuccessFactors}
• Business impact: {...}