Update RemoteConnectionInfo version constants (#52780)

Recent work was implemented to add proxy mode support for remote
conneciton info. This work has been backported to 7.6. This commit
updates the version constants on master to reflect this fact.

Author: Tim-Brooks

server/src/main/java/org/elasticsearch/transport/RemoteConnectionInfo.java

@@ -51,8 +51,7 @@ public RemoteConnectionInfo(String clusterAlias, ModeInfo modeInfo, TimeValue in
     }
 
     public RemoteConnectionInfo(StreamInput input) throws IOException {
-        // TODO: Change to 7.6 after backport
-        if (input.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (input.getVersion().onOrAfter(Version.V_7_6_0)) {
             RemoteConnectionStrategy.ConnectionStrategy mode = input.readEnum(RemoteConnectionStrategy.ConnectionStrategy.class);
             modeInfo = mode.getReader().read(input);
             initialConnectionTimeout = input.readTimeValue();
@@ -91,8 +90,7 @@ public boolean isSkipUnavailable() {
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
-        // TODO: Change to 7.6 after backport
-        if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_7_6_0)) {
             out.writeEnum(modeInfo.modeType());
             modeInfo.writeTo(out);
             out.writeTimeValue(initialConnectionTimeout);