[BUGFIX] Remove empty brackets when configuration type is unknown

When reenable the default configuration field rendering it might be happen
that type description es empty and only the brackets are shown. Those
could be dropped.

Fixes: #43043
Releases: 6.0

Change-Id: Ib732eaf5bca9128c0d253cfa83013ec7e9b007cf
Reviewed-on: http://review.typo3.org/16773
Reviewed-by: Nicole Cordes
Tested-by: Nicole Cordes
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel

typo3/sysext/extensionmanager/Resources/Private/Templates/Configuration/ShowConfigurationForm.html

@@ -36,7 +36,13 @@
 											<span style="background:red; padding:1px 2px; color:#fff; font-weight:bold;">{item.highlight}</span>
 										</f:if>
 										<em:form.typoScriptConstants configuration="{item}" />
-										<span class="info">(<f:translate key="extConfTemplate.type.{item.type}" />)</span>
+										<f:alias map="{label: '{f:translate(key: \'extConfTemplate.type.{item.type}\')}'}">
+											<f:if condition="{label}">
+												<f:then>
+													<span class="info">({label})</span>
+												</f:then>
+											</f:if>
+										</f:alias>
 									</div>
 								</f:for>
 								<f:form.submit value="{f:translate(key:'extConfTemplate.submitButton')}" />