fix(session): fix invalid data type in SessionRegenerate

[liubin]

In some case,in my own I had run two core instance with redis is set to 127.0.0.1:6379(each core is connected to the redis instance in the same node), when login the portal, I got the error:

failed to save sid=0aea8ed3cb978163db227608b7662f03, where oldsid=7b7b626828df9e00911484c8c6693692, error: failed to encode value, key 0aea8ed3cb978163db227608b7662f03, error: object type invalid, ""

the codec in session is gobCodec, in its Encode func:

func (*gobCodec) Encode(v any) ([]byte, error) {
	if vm, ok := v.(map[any]any); ok {
		return session.EncodeGob(vm)
	}

	return nil, errors.Errorf("object type invalid, %#v", v)
}

The cache's Save can't accept an value of "", but should be map[any]any{}.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 65.87%. Comparing base (c8c11b4) to head (37765b9).
⚠️ Report is 619 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main   #22726       +/-   ##
===========================================
+ Coverage   45.36%   65.87%   +20.50%     
===========================================
  Files         244     1073      +829     
  Lines       13333   116279   +102946     
  Branches     2719     2931      +212     
===========================================
+ Hits         6049    76594    +70545     
- Misses       6983    35438    +28455     
- Partials      301     4247     +3946     

Flag	Coverage Δ
unittests	65.87% <100.00%> (+20.50%)	⬆️

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Files with missing lines	Coverage Δ
src/core/session/session.go	37.60% <100.00%> (ø)

... and 987 files with indirect coverage changes

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[chlins]

lgtm

[wy65701436]

lgtm