Add second copy icon for value only

[yurishkuro]

Which problem is this PR solving?

• Resolves [Feature]: copy log entry VALUE as is #1503

Short description of the changes

• Adds a second Copy icon that copies value only
• Change Copy JSON icon to snippets, to be visually different
• Reduce fade-out time for tooltip

Original Copy JSON was added in #292 / #312.

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.03 ⚠️

Comparison is base (4834ea7) 95.63% compared to head (a7c576d) 95.60%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1505      +/-   ##
==========================================
- Coverage   95.63%   95.60%   -0.03%     
==========================================
  Files         245      245              
  Lines        7712     7712              
  Branches     2028     2028              
==========================================
- Hits         7375     7373       -2     
- Misses        337      339       +2     

Impacted Files	Coverage Δ
.../TraceTimelineViewer/SpanDetail/KeyValuesTable.tsx	97.82% <ø> (ø)
...kages/jaeger-ui/src/components/common/CopyIcon.tsx	100.00% <ø> (ø)

... and 1 file with indirect coverage changes

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