fix(domains): don't render CDN info message as an error in DNS tooltip

[AbiRaditya]

What is this PR about?

validateDomain treats a CDN-fronted domain as valid, but reuses the error field to carry the provider's informational warning:

// packages/server/src/services/domain.ts
if (cdnProvider) {
    return { isValid: true, resolvedIp, cdnProvider: cdnProvider.displayName, error: cdnProvider.warningMessage };
}

show-domains.tsx already untangles this when storing state (message: result.error && result.isValid ? result.error : undefined), and the badge reads message to render the green "Behind Cloudflare" label correctly. The tooltip, however, branched on error alone — so the informational text was displayed under a red Error: heading, as reported in #4910.

This checks the valid + message case first, mirroring the distinction the badge already makes.

Note that the same tooltip is duplicated in two places, so both are fixed:

• columns.tsx — the domains table view
• show-domains.tsx — the card view, which is the one in the issue screenshot ("Behind Cloudflare")

Fixing only the table view would leave the reported repro unchanged.

Checklist

Before submitting this PR, please make sure that:

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
• You have tested this PR in your local instance.

Repro for anyone verifying: detectCDNProvider matches the resolved IP against CDN ranges, so any Cloudflare-fronted domain (e.g. discord.com) added as an application domain will hit the CDN branch — you don't need to own a domain on Cloudflare.

Issues related (if applicable)

closes #4910

Screenshots (if applicable)