fix(targets): Include SCHEMA message count in target logs

[edgarrmondragon]

From a (private) Slack conversation, it seems that we're missing the SCHEMA message count which makes it seem that the total is missing something.

Example of new output:

2023-07-07 12:46:08,109 | INFO     | target-csv           | Target 'target-csv' completed reading 262 lines of input (2 schemas, 257 records, 0 batch manifests, 3 state messages).

[codecov]

Codecov Report

Merging #1820 (82cbba6) into main (5bc4c57) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #1820   +/-   ##
=======================================
  Coverage   86.42%   86.42%           
=======================================
  Files          59       59           
  Lines        4996     4996           
  Branches      816      816           
=======================================
  Hits         4318     4318           
  Misses        479      479           
  Partials      199      199           

Impacted Files	Coverage Δ
singer_sdk/target_base.py	92.55% <ø> (ø)

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[pnadolny13]

@edgarrmondragon LGTM!