feat(ui5-combobox, ui5-multi-combobox): clear icon implementation

[MapTo0]

No description provided.

[MapTo0]

FIXES #7839

[niyap]

1. After the change is submitted, we have to adjust the documentation according to the latest guidelines and push a commit to the Nayden's change if it is not submitted yet.
2. change event: sap.m.ComboBox - when random value is entered and then clear icon is pressed - change event is NOT fired. When an item is selected and then clear icon is pressed - change event is fired. ui-combobox - when random value is entered and clear icon is pressed - change event is fired. When an item is selected and the clear icon is pressed - change event is NOT fired. ui5-multi-combobox: no change event when value is deleted, even custom value is allowed - is that correct, fired for ui-combobox but no for ui5-multi-combobox. Overall that inconsistency is strange.
3. input event: sap.m.(Multi)ComboBox - input event is NOT fired when clear icon is pressed, no matter random value or selected item is deleted. ui5-(multi-)combobox: input event is fired when clear icon is pressed both when selected item and random values are deleted.
4. input event mobile: ui5-combobox: check the sample test page on mobile device and especially the counters for input event - they increases constantly without any interaction (not presented on master). sap.m.(Multi)ComboBox - INPUT event is not fired on mobile device when the clear icon is pressed. ui5-multi-combobox: input event if fired when clear icon is pressed on mobile
5. For ui5-input the property is called "effectiveShowClearIcon", for ui5-(multi-)combobox: " _effectiveShowClearIcon" - isn't it better to be consistent?

[niyap]

1. Nayden's change related to the documentation is merged, so please pull the main and adjust the newly added documentation accordingly.
2. Let's discuss tomorrow with the team, whether we expect input event to be fired when clear icon is pressed.

[niyap]

1. Nayden's change related to the documentation is merged, so please pull the main and adjust the newly added documentation accordingly.
2. Let's discuss tomorrow with the team, whether we expect input event to be fired when clear icon is pressed.

After a discussion with the team, we have the agreement that the behaviour is expected, but we have to enhance the input event documentation. Currently, its definition is: "Fired when typing in input.(combobox)/ Fired when the value of the component changes at each keystroke(multi-combobox)", we have to adjust it with the information about the clear icon and the fact that input event is also fired when the clear icon is pressed