fix(openvpn): set default mssfix to 1320 for all providers with no default

- Partially address #2533

internal/provider/ipvanish/openvpnconf.go

@@ -10,6 +10,7 @@ import (
 func (p *Provider) OpenVPNConfig(connection models.Connection,
 	settings settings.OpenVPN, ipv6Supported bool,
 ) (lines []string) {
+	//nolint:mnd
 	providerSettings := utils.OpenVPNProviderSettings{
 		AuthUserPass: true,
 		Ciphers: []string{
@@ -19,6 +20,7 @@ func (p *Provider) OpenVPNConfig(connection models.Connection,
 		VerifyX509Type: "name",
 		TLSCipher:      "TLS-DHE-RSA-WITH-AES-256-CBC-SHA:TLS-DHE-DSS-WITH-AES-256-CBC-SHA:TLS-RSA-WITH-AES-256-CBC-SHA",
 		CAs:            []string{"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"}, //nolint:lll
+		MssFix:         1320,
 	}
 	return utils.OpenVPNConfig(providerSettings, connection, settings, ipv6Supported)
 }