fix: update regex to allow special and umlaut characters

[JordanGerada3]

Description

• Update central search field regex validation code to allow special characters and umlauts

Why

Companies that contained special characters or umlauts were not searchable via the search field.

Issue

#164

Checklist

• I have followed the contributing guidelines
• I have added copyright and license headers, footers (for .md files) or files (for images)
• I have performed a self-review of my changes
• I have successfully tested my changes
• I have added comments in the default values.yaml file with helm-docs syntax ('# -- ') if relevant for installation
• I have commented my changes, particularly in hard-to-understand areas

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[typecastcloud]

Looks good to me! Search should be at least as permissive as company names allowed via onboarding.
Small change. 👍

[evegufy]

@oyo could you please also review?