Fix references to optional supportedConfigurations (#536)

Closes #529


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<a href="https://pr-preview.s3.amazonaws.com/w3c/encrypted-media/pull/536.html" title="Last updated on May 14, 2024, 9:34 PM UTC (7c04de8)">Preview</a> | <a href="https://pr-preview.s3.amazonaws.com/w3c/encrypted-media/536/c01e7e5...7c04de8.html" title="Last updated on May 14, 2024, 9:34 PM UTC (7c04de8)">Diff</a>

encrypted-media-respec.html

@@ -1052,8 +1052,7 @@ <h2>
                 and use a {{MediaKeys}} object with the provided configuration.
               </p>
               <p>
-                Requests access to the specified [=Key System=]. When
-                <code>supportedConfigurations</code> is specified, the configuration specified by
+                Requests access to the specified [=Key System=]. The configuration specified by
                 at least one of its elements must be supported. The resulting
                 {{MediaKeySystemAccess}} will correspond to the first such element.
               </p>
@@ -1063,7 +1062,7 @@ <h2>
               </p>
               <p>
                 If the <code>keySystem</code> is not supported or not allowed (in at least one of
-                the <code>supportedConfigurations</code>, if specified), the promise is rejected.
+                the <code>supportedConfigurations</code>), the promise is rejected.
                 Otherwise, it is resolved with a new {{MediaKeySystemAccess}} object.
               </p>
               <div class="note">