[pkg/ottl] Introduce profiles based e2e tests (open-telemetry#40931)

#### Description

Introduce OTTL e2e tests based on profiles.
The tests uncovered an issue in accessAttributesKey(), which is fixed in
this PR.

The e2e test have been requested
[here](open-telemetry#39416 (comment))
by @TylerHelmuth.

#### Link to tracking issue
Fixes open-telemetry#40738

#### THIS PR WILL ONLY WORK ON TOP OF
open-telemetry#39416.

---------

Co-authored-by: Tyler Helmuth <[email protected]>
Co-authored-by: Edmo Vamerlatti Costa <[email protected]>

Author: 3 people

.chloggen/ottl-e2e-profiles.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: pkg/ottl
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix an issue where the attribute values were amended in the profiles dictionary.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [40738]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

pkg/ottl/contexts/internal/ctxprofile/profile.go

@@ -348,11 +348,29 @@ func accessAttributesKey[K Context](key []ottl.Key[K]) ottl.StandardGetSetter[K]
 			if err != nil {
 				return err
 			}
-			v := pcommon.NewValueEmpty()
+			v := getAttributeValue(tCtx, *newKey)
 			if err = ctxutil.SetIndexableValue[K](ctx, tCtx, v, val, key[1:]); err != nil {
 				return err
 			}
 			return pprofile.PutAttribute(tCtx.GetProfilesDictionary().AttributeTable(), tCtx.GetProfile(), *newKey, v)
 		},
 	}
 }
+
+func getAttributeValue[K ProfileContext](tCtx K, key string) pcommon.Value {
+	// Find the index of the attribute in the profile's attribute indices
+	// and return the corresponding value from the attribute table.
+	table := tCtx.GetProfilesDictionary().AttributeTable()
+	indices := tCtx.GetProfile().AttributeIndices().AsRaw()
+
+	for _, tableIndex := range indices {
+		attr := table.At(int(tableIndex))
+		if attr.Key() == key {
+			v := pcommon.NewValueEmpty()
+			attr.Value().CopyTo(v)
+			return v
+		}
+	}
+
+	return pcommon.NewValueEmpty()
+}