update "template" api to always return less than 4mb string payload

[Tomcli]

/kind feature

Description:
The template api right now is calling grpc to send its payload as string to the end users/UI. Which it has a limit of 4mb on all the data in its protocol. We need to make sure the tekton yaml returned as string in this case is always less than 4mb.

Additional information:
[Miscellaneous information that will assist in solving the issue.]