chore(pkger): improve error handling in service

this provides influxdb.Errors whenever possible from the pker service layer.
the behavior that caused the error is somewhat implicated in the errro code.
it is not perfect but is a big step forward. using the http server/client to
run pkger stuff makes it abundantly clear the errors need to be communicated
better.

closes: #16313

pkger/parser.go

@@ -1421,7 +1421,40 @@ func (e *parseErr) ValidationErrs() []ValidationErr {
 			errs = append(errs, traverseErrs(rootErr, v)...)
 		}
 	}
-	return errs
+
+	// used to provide a means to == or != in the map lookup
+	// to remove duplicate errors
+	type key struct {
+		kind    string
+		fields  string
+		indexes string
+		reason  string
+	}
+
+	m := make(map[key]bool)
+	var out []ValidationErr
+	for _, verr := range errs {
+		k := key{
+			kind:   verr.Kind,
+			fields: strings.Join(verr.Fields, ":"),
+			reason: verr.Reason,
+		}
+		var indexes []string
+		for _, idx := range verr.Indexes {
+			if idx == nil {
+				continue
+			}
+			indexes = append(indexes, strconv.Itoa(*idx))
+		}
+		k.indexes = strings.Join(indexes, ":")
+		if m[k] {
+			continue
+		}
+		m[k] = true
+		out = append(out, verr)
+	}
+
+	return out
 }
 
 // ValidationErr represents an error during the parsing of a package.
@@ -1471,8 +1504,15 @@ func (e *parseErr) append(errs ...resourceErr) {
 // it will return nil values for the parseErr, making it unsafe
 // to use.
 func IsParseErr(err error) bool {
-	_, ok := err.(*parseErr)
-	return ok
+	if _, ok := err.(*parseErr); ok {
+		return true
+	}
+
+	iErr, ok := err.(*influxdb.Error)
+	if !ok {
+		return false
+	}
+	return IsParseErr(iErr.Err)
 }
 
 func normStr(s string) string {

pkger/parser_test.go

@@ -1,6 +1,7 @@
 package pkger
 
 import (
+	"errors"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -4338,6 +4339,60 @@ spec:
 	})
 }
 
+func Test_IsParseError(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      error
+		expected bool
+	}{
+		{
+			name:     "base case",
+			err:      &parseErr{},
+			expected: true,
+		},
+		{
+			name: "wrapped by influxdb error",
+			err: &influxdb.Error{
+				Err: &parseErr{},
+			},
+			expected: true,
+		},
+		{
+			name: "deeply nested in influxdb error",
+			err: &influxdb.Error{
+				Err: &influxdb.Error{
+					Err: &influxdb.Error{
+						Err: &influxdb.Error{
+							Err: &parseErr{},
+						},
+					},
+				},
+			},
+			expected: true,
+		},
+		{
+			name: "influxdb error without nested parse err",
+			err: &influxdb.Error{
+				Err: errors.New("nope"),
+			},
+			expected: false,
+		},
+		{
+			name:     "plain error",
+			err:      errors.New("nope"),
+			expected: false,
+		},
+	}
+
+	for _, tt := range tests {
+		fn := func(t *testing.T) {
+			isParseErr := IsParseErr(tt.err)
+			assert.Equal(t, tt.expected, isParseErr)
+		}
+		t.Run(tt.name, fn)
+	}
+}
+
 func Test_PkgValidationErr(t *testing.T) {
 	iPtr := func(i int) *int {
 		return &i