Use unique http client for indexer

[hannahhoward]

Goals

We have an inadvertent HTTP timeout for fetches from HTTP providers. It's because we share the HTTP default client with the indexer fetcher, and that sets a 1 minute timeout.

Implementation

• Use a unique client with the indexer

[codecov-commenter]

Codecov Report

Merging #280 (29356ef) into main (9622d8b) will increase coverage by 0.38%.
The diff coverage is 0.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #280      +/-   ##
==========================================
+ Coverage   71.25%   71.63%   +0.38%     
==========================================
  Files          70       70              
  Lines        6283     6283              
==========================================
+ Hits         4477     4501      +24     
+ Misses       1554     1540      -14     
+ Partials      252      242      -10     

Impacted Files	Coverage Δ
pkg/lassie/lassie.go	61.15% <0.00%> (ø)

... and 6 files with indirect coverage changes