add reconnect for lwm2m gateway

[rhoninl]

What this PR does / why we need it:
gateway lwm2m don't support reconnect, if connectin is lost, only can reconnect it by restart deployment or pod
Will this PR make the community happier?
yes
Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): fixes #

How is this PR tested

• unit test
• e2e test
• other (please specify)
  test by local cluste, cut down and restore the network

Special notes for your reviewer:

Release note:

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 86 lines in your changes missing coverage. Please review.

Project coverage is 33.06%. Comparing base (7af19e4) to head (ff5183a).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/gateway/lwm2m/client/lwm2m.go	0.00%	77 Missing ⚠️
pkg/gateway/lwm2m/gatewaylwm2m.go	0.00%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1075      +/-   ##
==========================================
- Coverage   33.42%   33.06%   -0.36%     
==========================================
  Files          55       55              
  Lines        4808     4875      +67     
==========================================
+ Hits         1607     1612       +5     
- Misses       3061     3124      +63     
+ Partials      140      139       -1     

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

[tomqin93]

@rhoninl added some comments

[tomqin93]

LGTM