fix(DASH): Inconsistent DRM across periods when using clearkeys (#8602)

Fixes #8559

Author: avelad

lib/drm/drm_utils.js

@@ -99,6 +99,19 @@ shaka.drm.DrmUtils = class {
           };
           commonDrms.push(mergedDrm);
           break;
+        } else {
+          const isClearkeys = (drmInfo) => {
+            const licenseServerUri = drmInfo.licenseServerUri;
+            if (!licenseServerUri) {
+              return false;
+            }
+            return licenseServerUri.startsWith('data:application/json;base64,');
+          };
+          if (isClearkeys(drm1)) {
+            commonDrms.push(drm1);
+          } else if (isClearkeys(drm2)) {
+            commonDrms.push(drm2);
+          }
         }
       }
     }