fix(qt): fix few gui issues

[UdjinM6]

Issue being fixed or feature implemented

• red #800000 looks ugly in Dark theme, use TS_ERROR like we did prior to 17453 backport (via backport: bitcoin#15584, #16060, #16465, #16477, #16680, #16714, #16941, #16991, #17453, #17696, #19058 (last batch for v19) #5255), also introduce TS_WARNING for #999900 to unify things
  before:

after:

using TS_WARNING in sendcoinsdialog:

• there are ugly borders in statusbar when running on windows, fix them via css

before:

after:

What was done?

How Has This Been Tested?

run dash-qt --regtest --nowallet --resetguisettings

Breaking Changes

n/a

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation
• I have assigned this pull request to a milestone (for repository code-owners and collaborators only)

[knst]

TS_WARNING and TS_ERROR looks so much better.

tACK

may be also update TS_ERROR to TS_WARNING here?

src/qt/sendcoinsdialog.cpp:
            questionString.append("<span style='" + GUIUtil::getThemedStyleQString(GUIUtil::ThemedStyle::TS_ERROR) + "'>");
            questionString.append(tr("Warning: Using %1 with %2 or more inputs can harm your privacy and is not recommended").arg(strCoinJoinName).arg(10));
...
src/qt/sendcoinsdialog.cpp:
        questionString.append("<span style='" + GUIUtil::getThemedStyleQString(GUIUtil::ThemedStyle::TS_ERROR) + "'>");
        questionString.append(tr("<b>(%1 of %2 entries displayed)</b>").arg(displayedEntries).arg(messageEntries));

[PastaPastaPasta]

utACK for squash merge