[MM-54562] Add panic recover to API handler

[streamer45]

Summary

We add a recover function to catch panics at the API level.

• A panic at this level won't cause the plugin to crash and potentially kill all running calls in the process.
• We get to log the stack trace at the error level and cleaned up correctly.

Example output:

{"timestamp":"2023-10-06 12:22:22.474 -06:00","level":"error","msg":"panic: runtime error: invalid memory address or nil pointer dereference","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:22"}
{"timestamp":"2023-10-06 12:22:22.474 -06:00","level":"error","msg":"goroutine 84 [running]:","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.474 -06:00","level":"error","msg":"runtime/debug.Stack()","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.474 -06:00","level":"error","msg":"runtime/debug/stack.go:24 +0x6b","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.475 -06:00","level":"error","msg":"main.(*Plugin).logPanic(0xc0000fc400, {0x1497980, 0x1d996a0})","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.475 -06:00","level":"error","msg":"github.com/mattermost/mattermost-plugin-calls/server/log.go:24 +0xca","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.475 -06:00","level":"error","msg":"main.(*Plugin).ServeHTTP.func1()","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.475 -06:00","level":"error","msg":"github.com/mattermost/mattermost-plugin-calls/server/api.go:518 +0x49","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.475 -06:00","level":"error","msg":"panic({0x1497980?, 0x1d996a0?})","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}
{"timestamp":"2023-10-06 12:22:22.475 -06:00","level":"error","msg":"runtime/panic.go:920 +0x290","caller":"app/plugin_api.go:984","plugin_id":"com.mattermost.calls","origin":"main.(*Plugin).logPanic log.go:25"}

Ticket Link

https://mattermost.atlassian.net/browse/MM-54562

[codecov-commenter]

Codecov Report

Attention: 9 lines in your changes are missing coverage. Please review.

Comparison is base (ca763c1) 5.32% compared to head (6f4db3a) 5.33%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff            @@
##            main    #547      +/-   ##
========================================
+ Coverage   5.32%   5.33%   +0.01%     
========================================
  Files         24      24              
  Lines       4469    4479      +10     
========================================
+ Hits         238     239       +1     
- Misses      4214    4222       +8     
- Partials      17      18       +1     

Files	Coverage Δ
server/api.go	1.48% <25.00%> (+0.20%)	⬆️
server/log.go	0.00% <0.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[cpoile]

Seems simple enough, nice addition.