Middlware can\'t handle special characters in common name

This issue is imported from pivotal - Originaly created at Jul 8, 2021 by Peter Havekes

I have a user with common name :
🤖️🤣️🌎️😫️ ، ؛ ؟ ء آ

When he tries to log on to selfservice for the 2nd time an error occurs:

Jul  8 08:59:23 sa-test-app.surfconext.nl stepup-selfservice[30298]: {"channel":"app","level":"CRITICAL","message":"Exception when searching identity: \"Resource could not be read (status code 500)\"","context":[],"extra":{"server":"sa.test.surfconext.nl","application":"self-service","request_id":"82b3f603d08e4741096ddbe5f47be1e8"}}
Jul  8 08:59:23 sa-test-app.surfconext.nl stepup-selfservice[30298]: {"channel":"app","level":"ERROR","message":"Could not authenticate, Exception of type \"Surfnet\\StepupSelfService\\SelfServiceBundle\\Exception\\RuntimeException\" encountered: \"Exception when searching identity: \"Resource could not be read (status code 500)\"\"","context":[],"extra":{"server":"sa.test.surfconext.nl","application":"self-service","request_id":"82b3f603d08e4741096ddbe5f47be1e8"}}
Jul  8 08:59:23 sa-test-app.surfconext.nl stepup-selfservice[30298]: {"channel":"request","level":"CRITICAL","message":"Uncaught PHP Exception Surfnet\\StepupSelfService\\SelfServiceBundle\\Exception\\RuntimeException: \"Exception when searching identity: \"Resource could not be read (status code 500)\"\" at /opt/stepup/Stepup-SelfService-3.4.0-20210504124157Z-78ead56b2471c0ac9bfd47158554ba011f12fcfe/src/Surfnet/StepupSelfService/SelfServiceBundle/Service/IdentityService.php line 120","context":{"exception":{"class":"Surfnet\\StepupSelfService\\SelfServiceBundle\\Exception\\RuntimeException","message":"Exception when searching identity: \"Resource could not be read (status code 500)\"","code":0,"file":"/opt/stepup/Stepup-SelfService-3.4.0-20210504124157Z-78ead56b2471c0ac9bfd47158554ba011f12fcfe/src/Surfnet/StepupSelfService/SelfServiceBundle/Service/IdentityService.php:120","previous":{"class":"Surfnet\\StepupMiddlewareClient\\Exception\\ResourceReadException","message":"Resource could not be read (status code 500)","code":0,"file":"/opt/stepup/Stepup-SelfService-3.4.0-20210504124157Z-78ead56b2471c0ac9bfd47158554ba011f12fcfe/vendor/surfnet/stepup-middleware-client-bundle/src/Surfnet/StepupMiddlewareClient/Service/ApiService.php:84"}}},"extra":{"art":"19131","server":"sa.test.surfconext.nl","application":"self-service","request_id":"82b3f603d08e4741096ddbe5f47be1e8"}}

When searching for this users' email-adress in RA this error is shown:

Start by reproducing the failure with the supplied common name and email-search scenario. Inspect IdentityService.php at line 120 and the middleware client's ApiService.php at line 84, then trace the identity-search request and response. Done means identities with these special characters can be found successfully in self-service and RA without a 500 error.