Bulk up kopia wrapper error checking in BackupOp (#2281)

## Description

Expand error checking for kopia wrapper backup. Kopia may report a number of errors for a snapshot operation but may not give error structs for them. Handle this by checking if there were > 0 errors reported and making our own error struct for this if there are.

This will keep the system from reporting a successful backup when kopia had problems reading or uploading data. Errored files in kopia do not become part of the snapshot

## Does this PR need a docs update or release note?

- [ ] ✅ Yes, it's included
- [ ] 🕐 Yes, but in a later PR
- [x] ⛔ No 

## Type of change

- [ ] 🌻 Feature
- [x] 🐛 Bugfix
- [ ] 🗺️ Documentation
- [ ] 🤖 Test
- [ ] 💻 CI/Deployment
- [ ] 🧹 Tech Debt/Cleanup

## Issue(s)

* closes #2280 

## Test Plan

- [ ] 💪 Manual
- [ x ⚡ Unit test
- [x] 💚 E2E

src/internal/kopia/wrapper_test.go

@@ -447,6 +447,22 @@ func (suite *KopiaIntegrationSuite) TestBackupCollections_ReaderError() {
 	assert.False(t, stats.Incomplete)
 	// 5 file and 6 folder entries.
 	assert.Len(t, deets.Details().Entries, 5+6)
+
+	failedPath, err := suite.testPath2.Append(testFileName4, true)
+	require.NoError(t, err)
+
+	ic := i64counter{}
+
+	_, err = suite.w.RestoreMultipleItems(
+		suite.ctx,
+		string(stats.SnapshotID),
+		[]path.Path{failedPath},
+		&ic,
+	)
+	// Files that had an error shouldn't make a dir entry in kopia. If they do we
+	// may run into kopia-assisted incrementals issues because only mod time and
+	// not file size is checked for StreamingFiles.
+	assert.ErrorIs(t, err, ErrNotFound, "errored file is restorable")
 }
 
 type backedupFile struct {

src/internal/operations/backup.go

@@ -400,7 +400,32 @@ func consumeBackupDataCollections(
 		)
 	}
 
-	return bu.BackupCollections(ctx, bases, cs, tags, isIncremental)
+	kopiaStats, deets, itemsSourcedFromBase, err := bu.BackupCollections(
+		ctx,
+		bases,
+		cs,
+		tags,
+		isIncremental,
+	)
+
+	if kopiaStats.ErrorCount > 0 || kopiaStats.IgnoredErrorCount > 0 {
+		if err != nil {
+			err = errors.Wrapf(
+				err,
+				"kopia snapshot failed with %v catastrophic errors and %v ignored errors",
+				kopiaStats.ErrorCount,
+				kopiaStats.IgnoredErrorCount,
+			)
+		} else {
+			err = errors.Errorf(
+				"kopia snapshot failed with %v catastrophic errors and %v ignored errors",
+				kopiaStats.ErrorCount,
+				kopiaStats.IgnoredErrorCount,
+			)
+		}
+	}
+
+	return kopiaStats, deets, itemsSourcedFromBase, err
 }
 
 func matchesReason(reasons []kopia.Reason, p path.Path) bool {