fix: warn when code coverage doesn't meet requirement

[WillieRuemmele]

What does this PR do?

warns the user when the deployment doesn't meet the required code coverage

before

 ➜  sf project deploy validate --source-dir force-app/main/default --test-level RunAllTestsInOrg          
Validating Deployment of v57.0 metadata to [email protected] using the v57.0 SOAP API.
Deploy ID: 0Af5300000e2PMyCAM
Status: Failed | ████████████████████████████████████████ | 87/87 Components

Test Results Summary
Passing: 0
Failing: 0
Total: 0
Error (1): Failed to validate the deployment (0Af5300000e2PMyCAM).

after

 ➜  sf project:deploy:validate --source-dir force-app --test-level RunAllTestsInOrg
Validating Deployment of v57.0 metadata to [email protected] using the v57.0 SOAP API.
Deploy ID: 0Af5300000e2RDiCAM
Status: Failed | ████████████████████████████████████████ | 89/89 Components

Test Results Summary
Passing: 1
Failing: 0
Total: 1
Time: 421
 ›   Warning: Average test coverage across all Apex Classes and Triggers is 25%, at least 75% test coverage is required.
Error (1): Failed to validate the deployment (0Af5300000e2RDiCAM).

this is also printed on other deploy commands

 ➜  sf project deploy start --source-dir force-app --test-level RunAllTestsInOrg 
Deploying v57.0 metadata to [email protected] using the v57.0 SOAP API.
Deploy ID: 0Af5300000e2SL9CAM
Status: Failed | ████████████████████████████████████████ | 89/89 Components

Test Results Summary
Passing: 1
Failing: 0
Total: 1
Time: 339
 ›   Warning: Average test coverage across all Apex Classes and Triggers is 25%, at least 75% test coverage is required.

What issues does this PR fix or reference?

@W-13546168@
forcedotcom/cli#2179