Allow for unsecure SMTP settings for local unencrypted smtp relays (#10605)

This update provides the flexibility for users to configure SMTP for
local instances where encryption is not required. For environments using
an unencrypted SMTP relay or similar local instances that are not open
to the public, the end user can now choose to disable encryption. This
ensures flexibility in the configuration while still maintaining the
option for secure SMTP connections in other environments.

### From [NodeMailer](https://nodemailer.com/smtp/#tls-options)
**secure** – if true the connection will use TLS when connecting to
server. <mark>If false (the default) then TLS is used if server supports
the STARTTLS extension. In most cases set this value to true if you are
connecting to port 465. For port 587 or 25 keep it false.</mark>

**ignoreTLS** – <mark>if this is true and secure is false then TLS is
not used even if the server supports STARTTLS extension.</mark>

---------

Co-authored-by: Félix Malfait <felix.malfait@gmail.com>
Co-authored-by: Félix Malfait <felix@twenty.com>

packages/twenty-server/src/engine/core-modules/environment/environment-variables.ts

@@ -289,6 +289,15 @@ export class EnvironmentVariables {
   })
   EMAIL_SMTP_HOST: string;
 
+  @EnvironmentVariablesMetadata({
+    group: EnvironmentVariablesGroup.EmailSettings,
+    description: 'Use unsecure connection for SMTP',
+  })
+  @CastToBoolean()
+  @IsOptional()
+  @IsBoolean()
+  EMAIL_SMTP_NO_TLS = false;
+
   @EnvironmentVariablesMetadata({
     group: EnvironmentVariablesGroup.EmailSettings,
     description: 'SMTP port for sending emails',