Add capability to switch between storing notification content as binary data or text data

[darshanasbg]

$subject. Onboarding the changes introduced with,

• Add config to indicate the unicode support carbon-identity-framework#6142
• Store content based on the unicode support flag wso2-extensions/identity-event-handler-notification#284
  and enabling unicode support as the the default behavior.

Related to,

• Have the ability to support non-latin unicode characters for email templates #21235

[jenkins-is-staging]

PR builder started
Link: https://github.com/wso2/product-is/actions/runs/11954743955

[darshanasbg]

Notification template related tests passed locally.. Thus continue with merging, in order to avoid having complications in the dependency updater.

[INFO] Tests run: 255, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 207.209 s - in TestSuite
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 255, Failures: 0, Errors: 0, Skipped: 0

[jenkins-is-staging]

PR builder completed
Link: https://github.com/wso2/product-is/actions/runs/11954743955
Status: failure

[darshanasbg]

PR builder completed Link: https://github.com/wso2/product-is/actions/runs/11954743955 Status: failure

Failing email otp test since it use its own deployment toml file.

2024-11-21T15:55:12.9235323Z [INFO] Results:
2024-11-21T15:55:12.9235854Z [INFO] 
2024-11-21T15:55:12.9236292Z [ERROR] Failures: 
2024-11-21T15:55:12.9238106Z [ERROR] org.wso2.identity.integration.test.EmailOTPTestCase.testEmailOTPAuthentication(org.wso2.identity.integration.test.EmailOTPTestCase)
2024-11-21T15:55:12.9241348Z [ERROR]   Run 1: EmailOTPTestCase.testEmailOTPAuthentication:196 Error in redirection to email OTP authentication page for user: testuser1 expected:<true> but was:<false>
2024-11-21T15:55:12.9244477Z [ERROR]   Run 2: EmailOTPTestCase.testEmailOTPAuthentication:196 Error in redirection to email OTP authentication page for user: testuser2@wso2.com expected:<true> but was:<false>
2024-11-21T15:55:12.9246303Z [INFO] 
2024-11-21T15:55:12.9247125Z [ERROR]   LiteUserRegisterTestCase.testLiteUserRegistration:80 Lite user registration unsuccessful expected:<201> but was:<500>
2024-11-21T15:55:12.9248051Z [INFO]