Maven build has a typo when building Backwards Codecs [LUCENE-8782]

Noticed a trivial naming issue in the maven build, it builds "Lucene memory" twice!

[INFO] Reactor Build Order:
[INFO]
[INFO] Grandparent POM for Apache Lucene Core and Apache Solr [pom]
[INFO] Lucene parent POM [pom]
[INFO] Lucene Core [jar]
[INFO] Lucene codecs [jar]
[INFO] Lucene Test Framework [jar]
[INFO] Lucene Core tests [jar]
[INFO] Lucene Core aggregator POM [pom]
[INFO] Lucene Memory [jar]
[INFO] Lucene codecs tests [jar]
...
[INFO] Lucene QueryParsers [jar]
[INFO] Lucene Memory [jar]
[INFO] Lucene Highlighter [jar]

Turned out that backwards codecs has a typo in its pom.xml.template.  Attached a trivial patch to fix that.

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Migrated from [LUCENE-8782](https://issues.apache.org/jira/browse/LUCENE-8782) by Daniel Collins (@dcollins53)
Attachments: [LUCENE_codecs.patch](https://apache.github.io/lucene-jira-archive/attachments/LUCENE-8782/LUCENE_codecs.patch)

Open the Backwards Codecs pom.xml.template and compare its module name with the Maven reactor build order shown in the issue. Verify the naming typo is corrected and that the build lists the Backwards Codecs module distinctly from Lucene Memory.

Written by the indexing model from the issue text.