[FW][FIX] web: improve display of RGBA in colorpicker

[fw-bot]

Before this commit, the value of the RGBA in the colorpicker display was missing a spacing after the value for blue.

This commit add the spacing after this value to make the text more readable by the user.

task-4242209

Forward-Port-Of: odoo/odoo#182963

[robodoo]

[fw-bot]

@romo-odoo @qsm-odoo this PR targets master and is the last of the forward-port chain.

To merge the full chain, use

@robodoo r+

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[fw-bot]

@romo-odoo @qsm-odoo ci/runbot failed on this forward-port PR

[robodoo]

@qsm-odoo you may want to rebuild or fix this PR as it has failed CI.