fix(nmrs): switch to correct connection validation method

[cachebag]

This PR switches the saved connection lookup to use validate_connection_name() instead of validate_ssid(). Using the latter causes VPN profile names longer than 32-bytes to pass through.

Fixes #425

[Copilot]

Pull request overview

This PR fixes saved-connection lookups for VPN profiles by validating against connection-name rules (instead of Wi-Fi SSID rules), preventing legitimate VPN names >32 bytes from being rejected.

Changes:

• Replace SSID-based validation in saved connection lookup with validate_connection_name().
• Refactor early-return validation into a small helper (should_skip_lookup).
• Add unit tests to ensure long VPN names are permitted and blank names are skipped.

Comments suppressed due to low confidence (1)

nmrs/src/core/connection_settings.rs:82

• has_saved_connection is documented and parameter-named as SSID-specific, but it now relies on get_saved_connection_path which validates with validate_connection_name (255-byte limit) rather than SSID rules (32-byte limit). This changes behavior for SSID callers (including the public NetworkManager::has_saved_connection/get_saved_connection_path wrappers) by no longer rejecting overlong/invalid SSIDs. Consider either (a) renaming/updating the docs/parameter to reflect a generic “connection id/name” lookup, or (b) reintroducing validate_ssid() in the SSID-specific path so Wi-Fi SSID validation remains enforced while VPN names use validate_connection_name().

/// Checks whether a saved connection exists for the given SSID.
pub(crate) async fn has_saved_connection(conn: &Connection, ssid: &str) -> Result<bool> {
    get_saved_connection_path(conn, ssid)
        .await
        .map(|p| p.is_some())
}