Checkbox cannot be chosen when importing certificate

• Type: Bug
• Status: Open
• Resolution: Unresolved
• Affects Version/s: Master
• Fix Version/s: None
• Component/s: Application Security > SAML
• Labels: None
• Epic Link: SAML enhancements

Steps to reproduce:

1. Set up two instances of SAML, one as IdP and the other as SP.
2. Sign into IdP.
3. Navigate to Control Panel>Configuration>SAML Admin.
4. Click Replace Certificate button.
5. Click Import Certificate.
6. Click Select File and upload a singing PCKS12 certificate(eg. samlidp.p12)

Expected Result: The checkbox of the signing certificate should be chosen.
Acutal Result: The checkbox of the signing certificate cannot be chosen.

Note: The same issue occurs when importing encrypting PCKS12 certificate.