fix(filtered-search): trim whitespaces

[robertwilde]

Closes #1228

• add function to trim whitespaces that gets called on blur events
• add new custom blur event to make sure whitespaces are trimmed when user clicks outside of criterion

---

Documentation.
Examples.
Dashboards Demo.
Playwright report.

Coverage Reports:

• element-ng
• element-translate-ng

[gemini-code-assist]

Code Review

The pull request introduces a new whitespace trimming mechanism for filtered search inputs, triggered when a search input or criterion value loses focus. This involves adding new blur output events across si-filtered-search-typeahead, si-filtered-search-value, and si-filtered-search components, and implementing a trimWhitespaces method to clean up both the main search value and individual criterion values. Additionally, the tracking strategy for criteria in the si-filtered-search component's template was updated, and a test expectation was adjusted. A review comment suggests removing commented-out code in si-filtered-search.component.ts to improve code cleanliness.