Fix trace detail page's back button disappeared

[shwin0901]

Resolves #779

[codecov]

Codecov Report

Merging #805 (f012a70) into master (0c1fcd1) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head f012a70 differs from pull request most recent head 0ace963. Consider uploading reports for the commit 0ace963 to get more accurate results

@@           Coverage Diff           @@
##           master     #805   +/-   ##
=======================================
  Coverage   95.07%   95.07%           
=======================================
  Files         230      230           
  Lines        7010     7011    +1     
  Branches     1745     1746    +1     
=======================================
+ Hits         6665     6666    +1     
  Misses        339      339           
  Partials        6        6           

Impacted Files	Coverage Δ
...kages/jaeger-ui/src/components/TracePage/index.tsx	100.00% <100.00%> (ø)

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