Add support for showing validation errors in DynamicMaterialChipsComponent .

[padala]

I'm submitting a

[x] Bug / Regression
[ ] Feature Request / Proposal

I'm using

NG Dynamic Forms Version: `X.Y.Z`

[ ] Basic UI
[ ] Bootstrap UI  
[ ] Foundation UI
[ ] Ionic UI
[ ] Kendo UI
[x] Material  
[ ] NG Bootstrap
[ ] Prime NG

Description

Add support for showing validation errors for auto complete chip-list in material (DynamicMaterialChipsComponent).

`<mat-form-field [appearance]="model.getAdditional('appearance', 'legacy')"
[color]="model.getAdditional('color', 'primary')"
[floatLabel]="model.getAdditional('floatLabel', LABEL_OPTIONS && LABEL_OPTIONS['float'] || 'auto')"
[formGroup]="group"
[hideRequiredMarker]="model.getAdditional('hideRequiredMarker', false)"
[ngClass]="getClass('grid', 'control')">

<mat-chip-list #matChipList [formControlName]="model.id" [id]="id" [multiple]="true">

    <mat-chip *ngFor="let chip of chips; let index = index"
              [selectable]="false"
              (removed)="onChipRemoved(chip, index)">

        <span>{{ chip }}</span>

        <mat-icon matChipRemove>cancel</mat-icon>

    </mat-chip>

    <input matInput
           [matAutocomplete]="matAutocomplete"
           [matChipInputAddOnBlur]="model.getAdditional('matChipInputAddOnBlur', true)"
           [matChipInputFor]="matChipList"
           [matChipInputSeparatorKeyCodes]="model.getAdditional('matChipInputSeparatorKeyCodes', CHIPS_OPTIONS['separatorKeyCodes'])"
           [placeholder]="model.placeholder"
           (matChipInputTokenEnd)="onChipInputTokenEnd($event)"
           (blur)="onBlur($event)"
           (focus)="onFocus($event)"/>

    <mat-autocomplete #matAutocomplete="matAutocomplete"
                      [autoActiveFirstOption]="model.getAdditional('autoActiveFirstOption', AUTOCOMPLETE_OPTIONS['autoActiveFirstOption'])"
                      [disableRipple]="model.getAdditional('disableRipple', RIPPLE_OPTIONS && RIPPLE_OPTIONS['disabled'] || false)"
                      [displayWith]="model.getAdditional('displayWith', null)"
                      (optionSelected)="onChipSelected($event)">

        <mat-option *ngFor="let option of model.list$ | async" [value]="option">{{ option }}</mat-option>

    </mat-autocomplete>

</mat-chip-list>

` Above code doesn't have to show the validation errors. Following changes should fix the issue.

<mat-error *ngFor="let message of errorMessages">{{ message }}</mat-error>

I can raise a PR for the same.

[padala]

@udos86 Thanks for creating this library and actively maintaining it.
I've raised a PR to fix this issue #1053