Use mock assignment logger and verify it is being called (FF-1450)

[leoromanovsky]

added unit test to verify issue

--- FAIL: Test_e2e (2.06s)
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
    /Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141: 
        	Error Trace:	/Users/leo/src/golang-sdk/eppoclient/eppoclient_e2e_test.go:141
        	Error:      	Should have called with given arguments
        	Test:       	Test_e2e
        	Messages:   	Expected "LogAssignment" to have been called with:
        	            	[mock.Anything]
        	            	but no actual calls happened
FAIL
FAIL	github.com/Eppo-exp/golang-sdk/v2/eppoclient	2.364s
FAIL

resolution

Use passed logger from Config object.