[ACA-1968] Search input tunings

[suzanadirla]

PR Checklist

Please check if your PR fulfills the following requirements:

- [x] The commit message follows our guidelines: https://github.com/Alfresco/alfresco-content-app/blob/master/CONTRIBUTING.md#commit
- [ ] Tests for the changes have been added (for bug fixes / features)
- [ ] Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application / Infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: https://issues.alfresco.com/jira/browse/ACA-1968

What is the new behavior?

improved UX for the search input

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information