fix(tooltip): do not create arrow in SSR mode - 20.1.x

[RivaIvanova]

Closes #16273

Additional information (check all that apply):

• Bug fix
• New functionality
• Documentation
• Demos
• CI/CD

Checklist:

• All relevant tags have been applied to this PR
• This PR includes unit tests covering all the new code (test guidelines)
• This PR includes API docs for newly added methods/properties (api docs guidelines)
• This PR includes feature/README.MD updates for the feature docs
• This PR includes general feature table updates in the root README.MD
• This PR includes CHANGELOG.MD updates for newly added functionality
• This PR contains breaking changes
• This PR includes ng update migrations for the breaking changes (migrations guidelines)
• This PR includes behavioral changes and the feature specification has been updated with them

[Copilot]

Pull Request Overview

This PR fixes an SSR (Server-Side Rendering) issue by deferring tooltip arrow creation until after view initialization, ensuring it only happens in browser environments. The fix prevents errors when rendering tooltips on the server where DOM manipulation is not available.

• Moved arrow creation from constructor to ngAfterViewInit with browser environment check
• Updated tooltip target to handle cases where arrow may not exist yet
• Updated test assertions to reflect new DOM structure (arrow element is now at index 0 instead of 1)

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 7 comments.

File	Description
projects/igniteui-angular/src/lib/directives/tooltip/tooltip.directive.ts	Deferred arrow creation to ngAfterViewInit with platform check to prevent SSR issues
projects/igniteui-angular/src/lib/directives/tooltip/tooltip-target.directive.ts	Added null checks for arrow element and moved arrow visibility logic to ngAfterViewInit
projects/igniteui-angular/src/lib/grids/grid/grid-validation.spec.ts	Updated test assertions to access error message from correct DOM child index

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