Remove SystemApi annotation from EuiccManager.getOtaStatus()

EuiccManager.getOtaStatus() has been annotated as @SystemApi, but its
declaring class EuiccManager has not. Therefore, the method hasn't been
recognized as SystemApi (does not appear in system-current.txt) and no
app is using the method.

This hasn't been harmful, but will soon trigger CTS failures when we do
the exact match for SystemAPIs; a runtime entity annotated as @SystemApi
have to exist in the documented API (e.g. system-current.txt). So
removing this no-op annotation.

Bug: 67891551
Test: m -j checkapi
Change-Id: I570ef5e5c88b6b9162116d3d3a7b17367efa9d7f

telephony/java/android/telephony/euicc/EuiccManager.java

@@ -276,8 +276,8 @@ public class EuiccManager {
      *
      * @return the status of eUICC OTA. If {@link #isEnabled()} is false or the eUICC is not ready,
      *     {@link OtaStatus#EUICC_OTA_STATUS_UNAVAILABLE} will be returned.
+     * TODO(b/35851809): Make this a SystemApi.
      */
-    @SystemApi
     public int getOtaStatus() {
         if (!isEnabled()) {
             return EUICC_OTA_STATUS_UNAVAILABLE;