Adjust Pan external URL to match current site

[twalsh-ebi]

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Description

This PR would update the code to generate Pan Compara URLs, matching the base URL of an Ensembl sister site to be consistent with the current site (e.g. links to Vertebrates from staging-plants.ensembl.org would point to staging.ensembl.org).

Views affected

This would affect any Pan Compara view with links to Ensembl sister sites.

In the following examples, clicking on links for Ensembl sites other than Plants leads to a staging site from a sandbox page, and to a live site from a staging-site page:

• Pan Compara gene tree of A. thaliana gene AT1G07820 : sandbox vs staging
• Pan Compara orthologues for A. thaliana gene AT1G07820 : sandbox vs staging
• Pan Compara orthologues for Rice gene RPL5 : sandbox vs staging

Note that if you click on any of the bacterial genes in the RPL5 Pan-taxonomic tree, and click on the "Protein Summary" or "Protein Sequence" links in the gene's Zmenu, they lead to the respective views of that gene in the Ensembl Bacteria staging site, validating the changes in eg-web-common PR 151.

Possible complications

No complications expected, as the default behaviour is to point to the relevant Ensembl live site, as is done currently.

Merge conflicts

None detected.

Related JIRA Issues (EBI developers only)

• N/A