[client] Set up sysctl and routing table name only if routing rules are available

[lixmal]

Describe your changes

	rules := getSetupRules()
	for _, rule := range rules {
		if err := addRule(rule); err != nil {
			if errors.Is(err, syscall.EOPNOTSUPP) {
				log.Warnf("Rule operations are not supported, falling back to the legacy routing setup")
				setIsLegacy(true)
				return r.setupRefCounter(initAddresses, stateManager)
			}
			return nil, nil, fmt.Errorf("%s: %w", rule.description, err)
		}
	}

This code could fall back to the exclusion route setup in which case we never clean up previously set up sysctl opts. This PR moves the sysctl setup to after the fallback detection

Issue ticket number and link

Checklist

• Is it a bug fix
• Is a typo/documentation fix
• Is a feature enhancement
• It is a refactor
• Created tests that fail without the change (if possible)
• Extended the README / documentation, if necessary

[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

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