[SDK-2068] Added ScCid support and tests

[nsingh-branch]

Reference

SDK-2068 -- Collect, Persist, and Forward 'ScCid' value

Summary

Added support for collecting the Snapchat Click Identifier (ScCid) as a URL Query parameter. The parameter is collected and attached to each install, open, and v2/event request. Since ScCid is is session based, it is cleared whenever the app is backgrounded or terminated.

Motivation

To collect and forward the new ScCid URL query parameter.

Type Of Change

• [x] New feature (non-breaking change which adds functionality)

Testing Instructions

Open a link like https://branchtestbed.app.link/testlink&ScCid=c22f092d-0961-4dff-9110-009df25e1328 and observe that the ScCid is persistent and attached to the proper requests, then cleared appropriately.

cc @BranchMetrics/saas-sdk-devs for visibility.

[codecov[bot]]

Codecov Report

Merging #1282 (494048a) into master (731e879) will increase coverage by 0.07%. Report is 47 commits behind head on master. The diff coverage is 83.33%.

@@            Coverage Diff             @@
##           master    #1282      +/-   ##
==========================================
+ Coverage   51.42%   51.50%   +0.07%     
==========================================
  Files          76       76              
  Lines       10947    10970      +23     
  Branches     4238     4244       +6     
==========================================
+ Hits         5630     5650      +20     
- Misses       5060     5064       +4     
+ Partials      257      256       -1     

Files Changed	Coverage Δ
BranchSDK/BNCReferringURLUtility.m	95.79% <83.33%> (-1.59%)	:arrow_down:

... and 1 file with indirect coverage changes

[echo-branch]

@nsingh-branch Did we ever hear back from product about our concerns about this behavior?