feat(material/chips): add hideMultipleSelectionIndicator in mat-chip-listbox

[emiliodeg]

Feature Description

Currently there is an input hideSingleSelectionIndicator in <mat-chip-listbox />, but if we set multiple="true" there is no option to hide all of them. So we need a boolean input hideMultipleSelectionIndicator as we have in <mat-button-toggle-group />

Use Case

We want to use a multiple chip listbox indicating selected multi options without the indicator

[emiliodeg]

on the other hand, just having a hideSelectionIndicator. Could it be enough for both cases (single/multi)?

[Zaid-Shabab]

Hello, I am preparing for GSoC and interested in contributing to this project. Could you guide me to beginner issues?