Fix IPv6 ping header detection in connectivity test

Description

This PR fixes the ping header regex pattern to support both IPv4 and IPv6 formats in the connectivity test.

Currently, when running connectivity tests with IPv6, the ping command's header has a slightly different format:

• IPv4: PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data.
• IPv6: PING 2606:4700:4700::1111(2606:4700:4700::1111) 56 data bytes

The existing regex only matches the IPv4 format (bytes of data.), causing issues when testing with IPv6.

Changes

• Updated the pingHeaderPattern regex to match both IPv4 and IPv6 ping header formats
• The new pattern: ^PING .*(bytes of data\.|data bytes)

Testing

I created a test program to verify the updated regex pattern works with both IPv4 and IPv6 formats:

package main

import (
    "fmt"
    "regexp"
)

func main() {
    pingHeaderPattern := regexp.MustCompile(`^PING .*(bytes of data\.|data bytes)`)

    ipv4Header := "PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data."
    ipv6Header := "PING 2606:4700:4700::1111(2606:4700:4700::1111) 56 data bytes"

    fmt.Printf("IPv4 header matches: %v\n", pingHeaderPattern.MatchString(ipv4Header))
    fmt.Printf("IPv6 header matches: %v\n", pingHeaderPattern.MatchString(ipv6Header))
}

Output:

IPv4 header matches: true
IPv6 header matches: true

Related Issues

Fixes cilium/cilium-cli#2352