Add full domain name with protocol for Twitter tag

[brianlove]

Twitter requires a full URL, including protocol, not a relative path to the card image.

Closes https://github.com/georgetown-cset/eto-platform/issues/633

[github-actions[bot]]

No need for rebasing :+1: behind_count is 0 ahead_count is 1

[github-actions[bot]]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
637	425	67%	0%	🟢

New Files

No new covered files...

Modified Files

No covered modified files...

updated for commit: f9a3dcb by action🐍

[github-actions[bot]]

JavaScript Coverage

Summary

Lines	Statements	Branches	Functions
	68.84% (453/658)	56.31% (232/412)	70.4% (138/196)

Modified Files • (68%)

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	68.84	56.31	70.4	68.69
components	64.69	54.81	64.49	64.32
MetaTagsWrapper.jsx	0	0	0	0	6–13