Adds replication metrics to versions of MySQL older than 8.0.22 (open…

…-telemetry#35776)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
Version of MySQL older than 8.0.22 use the `show slave status` vs `show
replica status` view to retrieve replication metrics. This allows for
both the newer & older views to work and retrieve data for the two
actual replica metrics available (`mysql.replica.time_behind_source` &
`mysql.replica.sql_delay`).

<!-- Issue number (e.g. open-telemetry#1234) or full URL to issue, if applicable. -->
#### Link to tracking issue
Fixes open-telemetry#35217

<!--Describe what testing was performed and which tests were added.-->
#### Testing
Manual testing against MySQL versions 8.0, 8.0.37, & MariaDB Ver 15.1
Distrib 10.5.26-MariaDB

<!--Describe the documentation added.-->
#### Documentation
None needed

<!--Please delete paragraphs that you did not use before submitting.-->

.chloggen/mysqlreceiver_older_replica_metrics_support.yaml

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+# 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: mysqlreceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add replica metric support for versions of MySQL earlier than 8.0.22.
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [35217]
+
+# (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: []