catalog: Convert connectedProxies to sync.Map

[draychev]

To simplify things, this PR changes the

	connectedProxies     map[certificate.CommonName]connectedProxy		
	connectedProxiesLock sync.Mutex

with

	connectedProxies sync.Map

There are 2 other similar fields that will be changed with another PR to keep things simple and clean.

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Ran a quick test to verify the debug server works as expected;

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Affected area:

• New Functionality [ ]
• Documentation [ ]
• Install [ ]
• Control Plane [ ]
• CLI Tool [ ]
• Certificate Management [ ]
• Networking [ ]
• Metrics [ ]
• SMI Policy [ ]
• Security [ ]
• Tests [ ]
• CI System [ ]
• Performance [ ]
• Other [ ]

Please answer the following questions with yes/no.

• Does this change contain code from or inspired by another project? If so, did you notify the maintainers and provide attribution?

[codecov-io]

Codecov Report

Merging #2061 (c8e220f) into main (e533370) will decrease coverage by 0.02%.
The diff coverage is 76.92%.

@@            Coverage Diff             @@
##             main    #2061      +/-   ##
==========================================
- Coverage   57.80%   57.77%   -0.03%     
==========================================
  Files         141      141              
  Lines        5794     5790       -4     
==========================================
- Hits         3349     3345       -4     
  Misses       2443     2443              
  Partials        2        2              

Impacted Files	Coverage Δ
pkg/catalog/catalog.go	100.00% <ø> (ø)
pkg/catalog/repeater.go	29.62% <0.00%> (-1.14%)	⬇️
pkg/catalog/debugger.go	97.22% <100.00%> (+2.62%)	⬆️
pkg/catalog/proxy.go	100.00% <100.00%> (ø)

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