fix: update the onButtonClick logic to avoid clicks after subscribed

[shubhamv-ss]

Description

With reference to this PR, after the user subscribed to the app, the requested button was still clickable, resulting in an error.

• Updated the logic to prevent onClick on the Subscribe button

Why

• After the Subscribe button clicks, it still can be clicked, resulting in errors.

Issue

• https://github.com/eclipse-tractusx/portal-frontend/issues/984

Checklist

• [x] I have performed a self-review of my own code
• [x] I have successfully tested my changes locally

[sonarcloud[bot]]

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

See analysis details on SonarCloud