fix Undefined index: HTTP_USER_AGENT
fix Undefined index: HTTP_USER_AGENT

Signed-off-by: Helmut K. C. Tessarek <c46493c0e7c11a163fc2021316679a5bca26d3b4@evermeet.cx>

juliushaertl/issuetemplate,juliushaertl/issuetemplate