fix: enable search for ASNs below 100

[JainAarjav]

Description

This PR fixes the issue where ASNs with fewer than three characters (e.g., AS16, AS99) were not returning results due to the minimum character requirement in the search bar. The updated logic ensures:

• If the input starts with AS followed by a number, it directly searches for ASNs.
• Rest searches are still handled as general searches.

This fix ensures that all ASNs, regardless of their number length, return relevant results.

Related issue

Fixes #893

How Has This Been Tested?

• Tested with inputs like AS16, AS99, AS163, and AS2497 to confirm ASN results appear.
• Verified that searches for IP addresses, prefixes, IXPs, and other entities remain unaffected.

Screenshots (if appropriate)

Types of Changes

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[dpgiakatos]

Violation of contribution guidelines:
PRs from contributors who are not assigned to this issue will be automatically closed.