[frontend/backend] Adding platform messages if imap is not reachable

[Dimfacion]

Proposed changes

• If IMAP is enabled and IMAP is down or misconfigured, the platform should NOT fail to start #1269

Related issues

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[codecov]

Codecov Report

Attention: Patch coverage is 20.00000% with 28 lines in your changes missing coverage. Please review.

Project coverage is 28.55%. Comparing base (fc98339) to head (203209d).

Files	Patch %	Lines
...va/io/openbas/service/PlatformSettingsService.java	7.69%	12 Missing ⚠️
...o/openbas/injectors/email/service/ImapService.java	40.00%	9 Missing ⚠️
...enbas/rest/settings/response/PlatformSettings.java	0.00%	5 Missing ⚠️
...cutors/caldera/service/CalderaExecutorService.java	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #1284      +/-   ##
============================================
- Coverage     28.78%   28.55%   -0.24%     
+ Complexity     1286     1283       -3     
============================================
  Files           507      507              
  Lines         13007    13022      +15     
  Branches        736      741       +5     
============================================
- Hits           3744     3718      -26     
- Misses         9105     9146      +41     
  Partials        158      158              

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[RomuDeuxfois]

Look good to me.
The log will be full of this on the other hand

java.lang.IllegalStateException: Not connected
at org.eclipse.angus.mail.imap.IMAPStore.checkConnected(IMAPStore.java:1983) ~[jakarta.mail-2.0.2.jar:na]
at org.eclipse.angus.mail.imap.IMAPStore.getFolder(IMAPStore.java:1760) ~[jakarta.mail-2.0.2.jar:na]
at io.openbas.injectors.email.service.ImapService.syncFolders(ImapService.java:301) ~[classes/:na]
at io.openbas.injectors.email.service.ImapService.connectionListener(ImapService.java:325) ~[classes/:na]
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103) ~[na:na]
at java.base/java.lang.reflect.Method.invoke(Method.java:580) ~[na:na]
at org.springframework.scheduling.support.ScheduledMethodRunnable.runInternal(ScheduledMethodRunnable.java:130) ~[spring-context-6.1.1.jar:6.1.1]
at org.springframework.scheduling.support.ScheduledMethodRunnable.lambda$run$2(ScheduledMethodRunnable.java:124) ~[spring-context-6.1.1.jar:6.1.1]
at io.micrometer.observation.Observation.observe(Observation.java:499) ~[micrometer-observation-1.12.0.jar:1.12.0]
at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:124) ~[spring-context-6.1.1.jar:6.1.1]
at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) ~[spring-context-6.1.1.jar:6.1.1]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572) ~[na:na]
at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:358) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:1583) ~[na:na]