bug-fix: Lark(Feishu) notifications don't work

[xhkyyy]

This PR fix fails to send a notification to Lark(Feishu): code: 9499, msg: bad request.
This error is found in the Feishu document: https://open.feishu.cn/document/ukTMukTMukTM/ugjM14COyUjL4ITN

[haoel]

Thanks for this PR. So, the root cause is that the request body's JSON is invalid because of lacking the quotes, right?

[codecov-commenter]

Codecov Report

Merging #170 (1df5899) into main (8b5be29) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #170   +/-   ##
=======================================
  Coverage   93.15%   93.15%           
=======================================
  Files          46       46           
  Lines        3362     3362           
=======================================
  Hits         3132     3132           
  Misses        161      161           
  Partials       69       69           

Impacted Files	Coverage Δ
report/result.go	92.85% <100.00%> (ø)
report/sla.go	94.06% <100.00%> (ø)

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[xhkyyy]

Thanks for this PR. So, the root cause is that the request body's JSON is invalid because of lacking the quotes, right?

@haoel yes, and the StatusCode check is also wrong, it causes always an error value to be returned instead of nil.