Fix a log schema inconsistency

In JiraService, some structured logs for errors were sent with a Hash in
the error key, and some with a String. This frustrates Elasticsearch,
which is commonly used to store structured logs, causing it to have to
drop logs from one instance or the other due to the type mismatch.

app/models/project_services/jira_service.rb

@@ -229,7 +229,15 @@ class JiraService < IssueTrackerService
     jira_issue_transition_id.scan(Gitlab::Regex.jira_transition_id_regex).each do |transition_id|
       issue.transitions.build.save!(transition: { id: transition_id })
     rescue => error
-      log_error("Issue transition failed", error: error.message, client_url: client_url)
+      log_error(
+        "Issue transition failed",
+          error: {
+            exception_class: error.class.name,
+            exception_message: error.message,
+            exception_backtrace: Gitlab::BacktraceCleaner.clean_backtrace(error.backtrace)
+          },
+         client_url: client_url
+      )
       return false
     end
   end
@@ -354,7 +362,7 @@ class JiraService < IssueTrackerService
       error: {
         exception_class: error.class.name,
         exception_message: error.message,
-        exception_backtrace: error.backtrace.join("\n")
+        exception_backtrace: Gitlab::BacktraceCleaner.clean_backtrace(error.backtrace)
       }
     )
     nil

spec/models/project_services/jira_service_spec.rb

@@ -489,7 +489,14 @@ describe JiraService do
 
         @jira_service.close_issue(resource, ExternalIssue.new('JIRA-123', project))
 
-        expect(@jira_service).to have_received(:log_error).with("Issue transition failed", error: "Bad Request", client_url: "http://jira.example.com")
+        expect(@jira_service).to have_received(:log_error).with(
+          "Issue transition failed",
+          error: hash_including(
+            exception_class: 'StandardError',
+            exception_message: "Bad Request"
+          ),
+          client_url: "http://jira.example.com"
+        )
       end
 
       it 'calls the api with jira_issue_transition_id' do